FileBackend splitted into several util classes for separate concerns: AvatarUtil, StreamUtil, ImageUtil. Unused imports removed.

22 files changed, 771 insertions, 580 deletions

diff --git a/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java b/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java
index 9ec39de8..a9b09551 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java
+++ b/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java
@@ -7,6 +7,8 @@ import android.preference.PreferenceManager;
 
 import java.io.File;
 
+import de.thedevstack.conversationsplus.utils.ImageUtil;
+
 /**
  * This class is used to provide static access to the applicationcontext.
  */
@@ -23,8 +25,13 @@ public class ConversationsPlusApplication extends Application {
         super.onCreate();
         ConversationsPlusApplication.instance = this;
         ConversationsPlusPreferences.init(PreferenceManager.getDefaultSharedPreferences(getAppContext()));
+        ImageUtil.initBitmapCache();
     }
 
+    /**
+     * Returns the instance of the application
+     * @return this application instance
+     */
     public static ConversationsPlusApplication getInstance() {
         return ConversationsPlusApplication.instance;
     }
@@ -45,6 +52,11 @@ public class ConversationsPlusApplication extends Application {
         return ConversationsPlusApplication.instance.getFilesDir();
     }
 
+    /**
+     * Returns the version of the application.
+     * @see android.content.pm.PackageInfo#versionName
+     * @return a string representation of the version stored in packageInfo
+     */
     public static String getVersion() {
         final String packageName = ConversationsPlusApplication.getAppContext().getPackageName();
         if (packageName != null) {
@@ -58,10 +70,19 @@ public class ConversationsPlusApplication extends Application {
         }
     }
 
+    /**
+     * Returns the application's name.
+     * @return the name as it is defined in R.string.app_name
+     */
     public static String getName() {
         return ConversationsPlusApplication.getAppContext().getString(R.string.app_name);
     }
 
+    /**
+     * Returns the name and the version of this application.
+     * @see #getName() and #getVersion
+     * @return a concatination of name and version with a whitespace in between
+     */
     public static String getNameAndVersion() {
         return getName() + " " + getVersion();
     }
diff --git a/src/main/java/de/thedevstack/conversationsplus/crypto/PgpEngine.java b/src/main/java/de/thedevstack/conversationsplus/crypto/PgpEngine.java
index 531aca32..fe7eefdf 100644
--- a/src/main/java/de/thedevstack/conversationsplus/crypto/PgpEngine.java
+++ b/src/main/java/de/thedevstack/conversationsplus/crypto/PgpEngine.java
@@ -14,7 +14,7 @@ import org.openintents.openpgp.util.OpenPgpApi;
 import org.openintents.openpgp.util.OpenPgpApi.IOpenPgpCallback;
 
 import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
-import de.tzur.conversations.Settings;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.R;
 import de.thedevstack.conversationsplus.entities.Account;
 import de.thedevstack.conversationsplus.entities.Contact;
@@ -87,10 +87,8 @@ public class PgpEngine {
 			});
 		} else if (message.getType() == Message.TYPE_IMAGE || message.getType() == Message.TYPE_FILE) {
 			try {
-				final DownloadableFile inputFile = this.mXmppConnectionService
-						.getFileBackend().getFile(message, false);
-				final DownloadableFile outputFile = this.mXmppConnectionService
-						.getFileBackend().getFile(message, true);
+				final DownloadableFile inputFile = FileBackend.getFile(message, false);
+				final DownloadableFile outputFile = FileBackend.getFile(message, true);
 				outputFile.getParentFile().mkdirs();
 				outputFile.createNewFile();
 				InputStream is = new FileInputStream(inputFile);
@@ -103,7 +101,7 @@ public class PgpEngine {
 								OpenPgpApi.RESULT_CODE_ERROR)) {
 						case OpenPgpApi.RESULT_CODE_SUCCESS:
 							URL url = message.getFileParams().url;
-							mXmppConnectionService.getFileBackend().updateFileParams(message,url);
+							FileBackend.updateFileParams(message, url);
 							message.setEncryption(Message.ENCRYPTION_DECRYPTED);
 							PgpEngine.this.mXmppConnectionService
 									.updateMessage(message);
@@ -194,10 +192,8 @@ public class PgpEngine {
 			});
 		} else {
 			try {
-				DownloadableFile inputFile = this.mXmppConnectionService
-						.getFileBackend().getFile(message, true);
-				DownloadableFile outputFile = this.mXmppConnectionService
-						.getFileBackend().getFile(message, false);
+				DownloadableFile inputFile = FileBackend.getFile(message, true);
+				DownloadableFile outputFile = FileBackend.getFile(message, false);
 				outputFile.getParentFile().mkdirs();
 				outputFile.createNewFile();
 				InputStream is = new FileInputStream(inputFile);
diff --git a/src/main/java/de/thedevstack/conversationsplus/exceptions/FileCopyException.java b/src/main/java/de/thedevstack/conversationsplus/exceptions/FileCopyException.java
new file mode 100644
index 00000000..58363c0f
--- /dev/null
+++ b/src/main/java/de/thedevstack/conversationsplus/exceptions/FileCopyException.java
@@ -0,0 +1,14 @@
+package de.thedevstack.conversationsplus.exceptions;
+
+public class FileCopyException extends Exception {
+	private static final long serialVersionUID = -1010013599132881427L;
+	private int resId;
+
+	public FileCopyException(int resId) {
+		this.resId = resId;
+	}
+
+	public int getResId() {
+		return resId;
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/de/thedevstack/conversationsplus/http/HttpDownloadConnection.java b/src/main/java/de/thedevstack/conversationsplus/http/HttpDownloadConnection.java
index b7f3cc67..b958e57e 100644
--- a/src/main/java/de/thedevstack/conversationsplus/http/HttpDownloadConnection.java
+++ b/src/main/java/de/thedevstack/conversationsplus/http/HttpDownloadConnection.java
@@ -22,6 +22,7 @@ import de.thedevstack.conversationsplus.R;
 import de.thedevstack.conversationsplus.entities.Transferable;
 import de.thedevstack.conversationsplus.entities.DownloadableFile;
 import de.thedevstack.conversationsplus.entities.Message;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.services.XmppConnectionService;
 import de.thedevstack.conversationsplus.utils.CryptoHelper;
 
@@ -81,7 +82,7 @@ public class HttpDownloadConnection implements Transferable {
 				extension = lastPart;
 			}
 			message.setRelativeFilePath(message.getUuid()+"."+extension);
-			this.file = mXmppConnectionService.getFileBackend().getFile(message, false);
+			this.file = FileBackend.getFile(message, false);
 			String reference = mUrl.getRef();
 			if (reference != null && reference.length() == 96) {
 				this.file.setKey(CryptoHelper.hexToBytes(reference));
@@ -235,7 +236,7 @@ public class HttpDownloadConnection implements Transferable {
 
 		private void updateImageBounds() {
 			message.setType(Message.TYPE_FILE);
-			mXmppConnectionService.getFileBackend().updateFileParams(message, mUrl);
+			FileBackend.updateFileParams(message, mUrl);
 			mXmppConnectionService.updateMessage(message);
 		}
 
diff --git a/src/main/java/de/thedevstack/conversationsplus/http/HttpUploadConnection.java b/src/main/java/de/thedevstack/conversationsplus/http/HttpUploadConnection.java
index a9682718..05d3a129 100644
--- a/src/main/java/de/thedevstack/conversationsplus/http/HttpUploadConnection.java
+++ b/src/main/java/de/thedevstack/conversationsplus/http/HttpUploadConnection.java
@@ -21,6 +21,7 @@ import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.services.XmppConnectionService;
 import de.thedevstack.conversationsplus.ui.UiCallback;
 import de.thedevstack.conversationsplus.utils.CryptoHelper;
+import de.thedevstack.conversationsplus.utils.StreamUtil;
 import de.thedevstack.conversationsplus.utils.Xmlns;
 import de.thedevstack.conversationsplus.xml.Element;
 import de.thedevstack.conversationsplus.xmpp.OnIqPacketReceived;
@@ -85,7 +86,7 @@ public class HttpUploadConnection implements Transferable {
 		message.setTransferable(this);
 		mXmppConnectionService.markMessage(message,Message.STATUS_UNSEND);
 		this.account = message.getConversation().getAccount();
-		this.file = mXmppConnectionService.getFileBackend().getFile(message, false);
+		this.file = FileBackend.getFile(message, false);
 		this.file.setExpectedSize(this.file.getSize());
 
 		if (Config.ENCRYPT_ON_HTTP_UPLOADED) {
@@ -163,7 +164,7 @@ public class HttpUploadConnection implements Transferable {
 					if (key != null) {
 						mGetUrl = new URL(mGetUrl.toString() + "#" + CryptoHelper.bytesToHex(key));
 					}
-					mXmppConnectionService.getFileBackend().updateFileParams(message, mGetUrl);
+					FileBackend.updateFileParams(message, mGetUrl);
 					message.setTransferable(null);
 					message.setCounterpart(message.getConversation().getJid().toBareJid());
 					if (message.getEncryption() == Message.ENCRYPTION_DECRYPTED) {
@@ -193,8 +194,8 @@ public class HttpUploadConnection implements Transferable {
 				Log.d(Config.LOGTAG, e.getMessage());
 				fail();
 			} finally {
-				FileBackend.close(is);
-				FileBackend.close(os);
+				StreamUtil.close(is);
+				StreamUtil.close(os);
 				if (connection != null) {
 					connection.disconnect();
 				}
diff --git a/src/main/java/de/thedevstack/conversationsplus/parser/MessageParser.java b/src/main/java/de/thedevstack/conversationsplus/parser/MessageParser.java
index aa04df2b..f346eafc 100644
--- a/src/main/java/de/thedevstack/conversationsplus/parser/MessageParser.java
+++ b/src/main/java/de/thedevstack/conversationsplus/parser/MessageParser.java
@@ -16,6 +16,7 @@ import de.thedevstack.conversationsplus.entities.MucOptions;
 import de.thedevstack.conversationsplus.http.HttpConnectionManager;
 import de.thedevstack.conversationsplus.services.MessageArchiveService;
 import de.thedevstack.conversationsplus.services.XmppConnectionService;
+import de.thedevstack.conversationsplus.utils.AvatarUtil;
 import de.thedevstack.conversationsplus.utils.CryptoHelper;
 import de.thedevstack.conversationsplus.xml.Element;
 import de.thedevstack.conversationsplus.xmpp.OnMessagePacketReceived;
@@ -23,7 +24,6 @@ import de.thedevstack.conversationsplus.xmpp.chatstate.ChatState;
 import de.thedevstack.conversationsplus.xmpp.jid.Jid;
 import de.thedevstack.conversationsplus.xmpp.pep.Avatar;
 import de.thedevstack.conversationsplus.xmpp.stanzas.MessagePacket;
-import de.tzur.conversations.Settings;
 
 public class MessageParser extends AbstractParser implements
 		OnMessagePacketReceived {
@@ -143,7 +143,7 @@ public class MessageParser extends AbstractParser implements
 			Avatar avatar = Avatar.parseMetadata(items);
 			if (avatar != null) {
 				avatar.owner = from;
-				if (mXmppConnectionService.getFileBackend().isAvatarCached(avatar)) {
+				if (AvatarUtil.isAvatarCached(avatar)) {
 					if (account.getJid().toBareJid().equals(from)) {
 						if (account.setAvatar(avatar.getFilename())) {
 							mXmppConnectionService.databaseBackend.updateAccount(account);
diff --git a/src/main/java/de/thedevstack/conversationsplus/parser/PresenceParser.java b/src/main/java/de/thedevstack/conversationsplus/parser/PresenceParser.java
index 888845c2..ce52bbeb 100644
--- a/src/main/java/de/thedevstack/conversationsplus/parser/PresenceParser.java
+++ b/src/main/java/de/thedevstack/conversationsplus/parser/PresenceParser.java
@@ -10,6 +10,7 @@ import de.thedevstack.conversationsplus.entities.MucOptions;
 import de.thedevstack.conversationsplus.entities.Presences;
 import de.thedevstack.conversationsplus.generator.PresenceGenerator;
 import de.thedevstack.conversationsplus.services.XmppConnectionService;
+import de.thedevstack.conversationsplus.utils.AvatarUtil;
 import de.thedevstack.conversationsplus.xml.Element;
 import de.thedevstack.conversationsplus.xmpp.OnPresencePacketReceived;
 import de.thedevstack.conversationsplus.xmpp.jid.Jid;
@@ -58,7 +59,7 @@ public class PresenceParser extends AbstractParser implements
 			Avatar avatar = Avatar.parsePresence(packet.findChild("x", "vcard-temp:x:update"));
 			if (avatar != null && !contact.isSelf()) {
 				avatar.owner = from.toBareJid();
-				if (mXmppConnectionService.getFileBackend().isAvatarCached(avatar)) {
+				if (AvatarUtil.isAvatarCached(avatar)) {
 					if (contact.setAvatar(avatar)) {
 						mXmppConnectionService.getAvatarService().clear(contact);
 						mXmppConnectionService.updateConversationUi();
diff --git a/src/main/java/de/thedevstack/conversationsplus/persistance/FileBackend.java b/src/main/java/de/thedevstack/conversationsplus/persistance/FileBackend.java
index da5cbf09..7ee67a15 100644
--- a/src/main/java/de/thedevstack/conversationsplus/persistance/FileBackend.java
+++ b/src/main/java/de/thedevstack/conversationsplus/persistance/FileBackend.java
@@ -1,7 +1,5 @@
 package de.thedevstack.conversationsplus.persistance;
 
-import java.io.ByteArrayOutputStream;
-import java.io.Closeable;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
@@ -9,58 +7,39 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URL;
-import java.security.DigestOutputStream;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.Locale;
 
-import android.database.Cursor;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
-import android.graphics.Canvas;
-import android.graphics.Matrix;
-import android.graphics.RectF;
-import android.media.ExifInterface;
 import android.net.Uri;
 import android.os.Environment;
-import android.provider.MediaStore;
-import android.util.Base64;
-import android.util.Base64OutputStream;
 import android.util.Log;
 import android.webkit.MimeTypeMap;
-import android.widget.ImageView;
 
 import de.thedevstack.conversationsplus.Config;
+import de.thedevstack.conversationsplus.ConversationsPlusApplication;
 import de.thedevstack.conversationsplus.R;
 import de.thedevstack.conversationsplus.entities.Transferable;
 import de.thedevstack.conversationsplus.entities.DownloadableFile;
 import de.thedevstack.conversationsplus.entities.Message;
-import de.thedevstack.conversationsplus.services.XmppConnectionService;
-import de.thedevstack.conversationsplus.utils.CryptoHelper;
-import de.thedevstack.conversationsplus.utils.ExifHelper;
-import de.thedevstack.conversationsplus.utils.FileHelper;
-import de.thedevstack.conversationsplus.xmpp.pep.Avatar;
+import de.thedevstack.conversationsplus.exceptions.FileCopyException;
+import de.thedevstack.conversationsplus.utils.ImageUtil;
+import de.thedevstack.conversationsplus.utils.StreamUtil;
 
-public class FileBackend {
+public final class FileBackend {
 
 	private static int IMAGE_SIZE = 1920;
 
-	private final SimpleDateFormat imageDateFormat = new SimpleDateFormat("yyyyMMdd_HHmmssSSS", Locale.US);
+	private static final SimpleDateFormat imageDateFormat = new SimpleDateFormat("yyyyMMdd_HHmmssSSS", Locale.US);
 
-	private XmppConnectionService mXmppConnectionService;
-
-	public FileBackend(XmppConnectionService service) {
-		this.mXmppConnectionService = service;
-	}
-
-	public DownloadableFile getFile(Message message) {
+	public static DownloadableFile getFile(Message message) {
 		return getFile(message, true);
 	}
 
-	public DownloadableFile getFile(Message message, boolean decrypted) {
+	public static DownloadableFile getFile(Message message, boolean decrypted) {
 		String path = message.getRelativeFilePath();
 		String extension;
 		if (path != null && !path.isEmpty()) {
@@ -102,50 +81,19 @@ public class FileBackend {
 			+ "/Conversations/";
 	}
 
-	public Bitmap resize(Bitmap originalBitmap, int size) {
-		int w = originalBitmap.getWidth();
-		int h = originalBitmap.getHeight();
-		if (Math.max(w, h) > size) {
-			int scalledW;
-			int scalledH;
-			if (w <= h) {
-				scalledW = (int) (w / ((double) h / size));
-				scalledH = size;
-			} else {
-				scalledW = size;
-				scalledH = (int) (h / ((double) w / size));
-			}
-			return Bitmap.createScaledBitmap(originalBitmap, scalledW, scalledH, true);
-		} else {
-			return originalBitmap;
-		}
-	}
-
-	public Bitmap rotate(Bitmap bitmap, int degree) {
-		int w = bitmap.getWidth();
-		int h = bitmap.getHeight();
-		Matrix mtx = new Matrix();
-		mtx.postRotate(degree);
-		return Bitmap.createBitmap(bitmap, 0, 0, w, h, mtx, true);
-	}
-
-	public String getOriginalPath(Uri uri) {
-		return FileHelper.getRealPathFromUri(uri);
-	}
-
-	public DownloadableFile copyFileToPrivateStorage(Message message, Uri uri) throws FileCopyException {
+	public static DownloadableFile copyFileToPrivateStorage(Message message, Uri uri) throws FileCopyException {
 		Log.d(Config.LOGTAG, "copy " + uri.toString() + " to private storage");
-		String mime = mXmppConnectionService.getContentResolver().getType(uri);
+		String mime = ConversationsPlusApplication.getInstance().getContentResolver().getType(uri);
 		String extension = MimeTypeMap.getSingleton().getExtensionFromMimeType(mime);
 		message.setRelativeFilePath(message.getUuid() + "." + extension);
-		DownloadableFile file = mXmppConnectionService.getFileBackend().getFile(message);
+		DownloadableFile file = getFile(message);
 		file.getParentFile().mkdirs();
 		OutputStream os = null;
 		InputStream is = null;
 		try {
 			file.createNewFile();
 			os = new FileOutputStream(file);
-			is = mXmppConnectionService.getContentResolver().openInputStream(uri);
+			is = StreamUtil.openInputStreamFromContentResolver(uri);
 			byte[] buffer = new byte[1024];
 			int length;
 			while ((length = is.read(buffer)) > 0) {
@@ -158,19 +106,19 @@ public class FileBackend {
 			e.printStackTrace();
 			throw new FileCopyException(R.string.error_io_exception);
 		} finally {
-			close(os);
-			close(is);
+			StreamUtil.close(os);
+			StreamUtil.close(is);
 		}
-		Log.d(Config.LOGTAG, "output file name " + mXmppConnectionService.getFileBackend().getFile(message));
+		Log.d(Config.LOGTAG, "output file name " + file);
 		return file;
 	}
 
-	public DownloadableFile copyImageToPrivateStorage(Message message, Uri image)
+	public static DownloadableFile copyImageToPrivateStorage(Message message, Uri image)
 			throws FileCopyException {
-		return this.copyImageToPrivateStorage(message, image, 0);
+		return copyImageToPrivateStorage(message, image, 0);
 	}
 
-	private DownloadableFile copyImageToPrivateStorage(Message message,
+	private static DownloadableFile copyImageToPrivateStorage(Message message,
 			Uri image, int sampleSize) throws FileCopyException {
 		DownloadableFile file = getFile(message);
 		file.getParentFile().mkdirs();
@@ -178,7 +126,7 @@ public class FileBackend {
 		OutputStream os = null;
 		try {
 			file.createNewFile();
-			is = mXmppConnectionService.getContentResolver().openInputStream(image);
+			is = StreamUtil.openInputStreamFromContentResolver(image);
 			os = new FileOutputStream(file);
 
 			Bitmap originalBitmap;
@@ -191,10 +139,10 @@ public class FileBackend {
 			if (originalBitmap == null) {
 				throw new FileCopyException(R.string.error_not_an_image_file);
 			}
-			Bitmap scaledBitmap = resize(originalBitmap, IMAGE_SIZE);
-			int rotation = getRotation(image);
+			Bitmap scaledBitmap = ImageUtil.resize(originalBitmap, IMAGE_SIZE);
+			int rotation = ImageUtil.getRotation(image);
 			if (rotation > 0) {
-				scaledBitmap = rotate(scaledBitmap, rotation);
+				scaledBitmap = ImageUtil.rotate(scaledBitmap, rotation);
 			}
 
 			boolean success = scaledBitmap.compress(Bitmap.CompressFormat.WEBP, 75, os);
@@ -224,286 +172,34 @@ public class FileBackend {
 		} catch (NullPointerException e) {
 			throw new FileCopyException(R.string.error_io_exception);
 		} finally {
-			close(os);
-			close(is);
-		}
-	}
-
-	private int getRotation(Uri image) {
-		InputStream is = null;
-		try {
-			is = mXmppConnectionService.getContentResolver().openInputStream(image);
-			return ExifHelper.getOrientation(is);
-		} catch (FileNotFoundException e) {
-			return 0;
-		} finally {
-			close(is);
-		}
-	}
-
-	public Bitmap getThumbnail(Message message, int size, boolean cacheOnly)
-			throws FileNotFoundException {
-		Bitmap thumbnail = mXmppConnectionService.getBitmapCache().get(
-				message.getUuid());
-		if ((thumbnail == null) && (!cacheOnly)) {
-			File file = getFile(message);
-			BitmapFactory.Options options = new BitmapFactory.Options();
-			options.inSampleSize = calcSampleSize(file, size);
-			Bitmap fullsize = BitmapFactory.decodeFile(file.getAbsolutePath(),options);
-			if (fullsize == null) {
-				throw new FileNotFoundException();
-			}
-			thumbnail = resize(fullsize, size);
-            try {
-                thumbnail = rotate(thumbnail, file.getAbsolutePath());
-            } catch (IOException e) {
-                throw new FileNotFoundException();
-            }
-            this.mXmppConnectionService.getBitmapCache().put(message.getUuid(),
-					thumbnail);
+			StreamUtil.close(os);
+			StreamUtil.close(is);
 		}
-		return thumbnail;
 	}
 
-    private Bitmap rotate(Bitmap original, String srcPath) throws IOException {
-        try {
-            ExifInterface exif = new ExifInterface(srcPath);
-            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);
-            int rotation = 0;
-            switch (orientation) {
-                case ExifInterface.ORIENTATION_ROTATE_90:
-                    rotation = 90;
-                    break;
-                case ExifInterface.ORIENTATION_ROTATE_180:
-                    rotation = 180;
-                    break;
-                case ExifInterface.ORIENTATION_ROTATE_270:
-                    rotation = 270;
-                    break;
-            }
-            if (rotation > 0) {
-                return rotate(original, rotation);
-            }
-        } catch (IOException e) {
-            Log.w("filebackend", "Error while rotating image, returning original");
-        }
-        return original;
-    }
-
-    public Uri getTakePhotoUri() {
+    public static Uri getTakePhotoUri() {
 		StringBuilder pathBuilder = new StringBuilder();
 		pathBuilder.append(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM));
 		pathBuilder.append('/');
 		pathBuilder.append("Camera");
 		pathBuilder.append('/');
-		pathBuilder.append("IMG_" + this.imageDateFormat.format(new Date()) + ".jpg");
+		pathBuilder.append("IMG_" + imageDateFormat.format(new Date()) + ".jpg");
 		Uri uri = Uri.parse("file://" + pathBuilder.toString());
 		File file = new File(uri.toString());
 		file.getParentFile().mkdirs();
 		return uri;
 	}
 
-	public Avatar getPepAvatar(Uri image, int size, Bitmap.CompressFormat format) {
-		try {
-			Avatar avatar = new Avatar();
-			Bitmap bm = cropCenterSquare(image, size);
-			if (bm == null) {
-				return null;
-			}
-			ByteArrayOutputStream mByteArrayOutputStream = new ByteArrayOutputStream();
-			Base64OutputStream mBase64OutputSttream = new Base64OutputStream(
-					mByteArrayOutputStream, Base64.DEFAULT);
-			MessageDigest digest = MessageDigest.getInstance("SHA-1");
-			DigestOutputStream mDigestOutputStream = new DigestOutputStream(
-					mBase64OutputSttream, digest);
-			if (!bm.compress(format, 75, mDigestOutputStream)) {
-				return null;
-			}
-			mDigestOutputStream.flush();
-			mDigestOutputStream.close();
-			avatar.sha1sum = CryptoHelper.bytesToHex(digest.digest());
-			avatar.image = new String(mByteArrayOutputStream.toByteArray());
-			return avatar;
-		} catch (NoSuchAlgorithmException e) {
-			return null;
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
-	public boolean isAvatarCached(Avatar avatar) {
-		File file = new File(getAvatarPath(avatar.getFilename()));
-		return file.exists();
-	}
-
-	public boolean save(Avatar avatar) {
-		File file;
-		if (isAvatarCached(avatar)) {
-			file = new File(getAvatarPath(avatar.getFilename()));
-		} else {
-			String filename = getAvatarPath(avatar.getFilename());
-			file = new File(filename + ".tmp");
-			file.getParentFile().mkdirs();
-			OutputStream os = null;
-			try {
-				file.createNewFile();
-				os = new FileOutputStream(file);
-				MessageDigest digest = MessageDigest.getInstance("SHA-1");
-				digest.reset();
-				DigestOutputStream mDigestOutputStream = new DigestOutputStream(os, digest);
-				mDigestOutputStream.write(avatar.getImageAsBytes());
-				mDigestOutputStream.flush();
-				mDigestOutputStream.close();
-				String sha1sum = CryptoHelper.bytesToHex(digest.digest());
-				if (sha1sum.equals(avatar.sha1sum)) {
-					file.renameTo(new File(filename));
-				} else {
-					Log.d(Config.LOGTAG, "sha1sum mismatch for " + avatar.owner);
-					file.delete();
-					return false;
-				}
-			} catch (FileNotFoundException e) {
-				return false;
-			} catch (IOException e) {
-				return false;
-			} catch (NoSuchAlgorithmException e) {
-				return false;
-			} finally {
-				close(os);
-			}
-		}
-		avatar.size = file.length();
-		return true;
-	}
-
-	public String getAvatarPath(String avatar) {
-		return mXmppConnectionService.getFilesDir().getAbsolutePath()+ "/avatars/" + avatar;
-	}
-
-	public Uri getAvatarUri(String avatar) {
-		return Uri.parse("file:" + getAvatarPath(avatar));
-	}
-
-	public Bitmap cropCenterSquare(Uri image, int size) {
-		if (image == null) {
-			return null;
-		}
-		InputStream is = null;
-		try {
-			BitmapFactory.Options options = new BitmapFactory.Options();
-			options.inSampleSize = calcSampleSize(image, size);
-			is = mXmppConnectionService.getContentResolver().openInputStream(image);
-			Bitmap input = BitmapFactory.decodeStream(is, null, options);
-			if (input == null) {
-				return null;
-			} else {
-				int rotation = getRotation(image);
-				if (rotation > 0) {
-					input = rotate(input, rotation);
-				}
-				return cropCenterSquare(input, size);
-			}
-		} catch (FileNotFoundException e) {
-			return null;
-		} finally {
-			close(is);
-		}
-	}
-
-	public Bitmap cropCenter(Uri image, int newHeight, int newWidth) {
-		if (image == null) {
-			return null;
-		}
-		InputStream is = null;
-		try {
-			BitmapFactory.Options options = new BitmapFactory.Options();
-			options.inSampleSize = calcSampleSize(image,Math.max(newHeight, newWidth));
-			is = mXmppConnectionService.getContentResolver().openInputStream(image);
-			Bitmap source = BitmapFactory.decodeStream(is, null, options);
-			if (source == null) {
-				return null;
-			}
-			int sourceWidth = source.getWidth();
-			int sourceHeight = source.getHeight();
-			float xScale = (float) newWidth / sourceWidth;
-			float yScale = (float) newHeight / sourceHeight;
-			float scale = Math.max(xScale, yScale);
-			float scaledWidth = scale * sourceWidth;
-			float scaledHeight = scale * sourceHeight;
-			float left = (newWidth - scaledWidth) / 2;
-			float top = (newHeight - scaledHeight) / 2;
-
-			RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
-			Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, Bitmap.Config.ARGB_8888);
-			Canvas canvas = new Canvas(dest);
-			canvas.drawBitmap(source, null, targetRect, null);
-			return dest;
-		} catch (FileNotFoundException e) {
-			return null;
-		} finally {
-			close(is);
-		}
-	}
-
-	public Bitmap cropCenterSquare(Bitmap input, int size) {
-		int w = input.getWidth();
-		int h = input.getHeight();
-
-		float scale = Math.max((float) size / h, (float) size / w);
-
-		float outWidth = scale * w;
-		float outHeight = scale * h;
-		float left = (size - outWidth) / 2;
-		float top = (size - outHeight) / 2;
-		RectF target = new RectF(left, top, left + outWidth, top + outHeight);
-
-		Bitmap output = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
-		Canvas canvas = new Canvas(output);
-		canvas.drawBitmap(input, null, target, null);
-		return output;
-	}
-
-	private int calcSampleSize(Uri image, int size) throws FileNotFoundException {
-		BitmapFactory.Options options = new BitmapFactory.Options();
-		options.inJustDecodeBounds = true;
-		BitmapFactory.decodeStream(mXmppConnectionService.getContentResolver().openInputStream(image), null, options);
-		return calcSampleSize(options, size);
-	}
-
-	private int calcSampleSize(File image, int size) {
-		BitmapFactory.Options options = new BitmapFactory.Options();
-		options.inJustDecodeBounds = true;
-		BitmapFactory.decodeFile(image.getAbsolutePath(), options);
-		return calcSampleSize(options, size);
-	}
-
-	private int calcSampleSize(BitmapFactory.Options options, int size) {
-		int height = options.outHeight;
-		int width = options.outWidth;
-		int inSampleSize = 1;
-
-		if (height > size || width > size) {
-			int halfHeight = height / 2;
-			int halfWidth = width / 2;
-
-			while ((halfHeight / inSampleSize) > size
-					&& (halfWidth / inSampleSize) > size) {
-				inSampleSize *= 2;
-			}
-		}
-		return inSampleSize;
-	}
-
-	public Uri getJingleFileUri(Message message) {
+	public static Uri getJingleFileUri(Message message) {
 		File file = getFile(message);
 		return Uri.parse("file://" + file.getAbsolutePath());
 	}
 
-	public void updateFileParams(Message message) {
+	public static void updateFileParams(Message message) {
 		updateFileParams(message,null);
 	}
 
-	public void updateFileParams(Message message, URL url) {
+	public static void updateFileParams(Message message, URL url) {
 		DownloadableFile file = getFile(message);
 		if (message.getType() == Message.TYPE_IMAGE || file.getMimeType().startsWith("image/")) {
 			BitmapFactory.Options options = new BitmapFactory.Options();
@@ -526,40 +222,11 @@ public class FileBackend {
 
 	}
 
-	public class FileCopyException extends Exception {
-		private static final long serialVersionUID = -1010013599132881427L;
-		private int resId;
-
-		public FileCopyException(int resId) {
-			this.resId = resId;
-		}
-
-		public int getResId() {
-			return resId;
-		}
-	}
-
-	public Bitmap getAvatar(String avatar, int size) {
-		if (avatar == null) {
-			return null;
-		}
-		Bitmap bm = cropCenter(getAvatarUri(avatar), size, size);
-		if (bm == null) {
-			return null;
-		}
-		return bm;
-	}
-
-	public boolean isFileAvailable(Message message) {
+	public static boolean isFileAvailable(Message message) {
 		return getFile(message).exists();
 	}
 
-	public static void close(Closeable stream) {
-		if (stream != null) {
-			try {
-				stream.close();
-			} catch (IOException e) {
-			}
-		}
-	}
-}
+    private FileBackend() {
+        // Static helper class
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/de/thedevstack/conversationsplus/services/AvatarService.java b/src/main/java/de/thedevstack/conversationsplus/services/AvatarService.java
index 7321fc08..83aa83e3 100644
--- a/src/main/java/de/thedevstack/conversationsplus/services/AvatarService.java
+++ b/src/main/java/de/thedevstack/conversationsplus/services/AvatarService.java
@@ -17,6 +17,8 @@ import de.thedevstack.conversationsplus.entities.Contact;
 import de.thedevstack.conversationsplus.entities.Conversation;
 import de.thedevstack.conversationsplus.entities.ListItem;
 import de.thedevstack.conversationsplus.entities.MucOptions;
+import de.thedevstack.conversationsplus.utils.AvatarUtil;
+import de.thedevstack.conversationsplus.utils.ImageUtil;
 import de.thedevstack.conversationsplus.utils.UIHelper;
 
 public class AvatarService {
@@ -40,28 +42,27 @@ public class AvatarService {
 
 	private Bitmap get(final Contact contact, final int size, boolean cachedOnly) {
 		final String KEY = key(contact, size);
-		Bitmap avatar = this.mXmppConnectionService.getBitmapCache().get(KEY);
+		Bitmap avatar = ImageUtil.getBitmapFromCache(KEY);
 		if (avatar != null || cachedOnly) {
 			return avatar;
 		}
 		if (contact.getProfilePhoto() != null) {
-			avatar = mXmppConnectionService.getFileBackend().cropCenterSquare(Uri.parse(contact.getProfilePhoto()), size);
+			avatar = ImageUtil.cropCenterSquare(Uri.parse(contact.getProfilePhoto()), size);
 		}
 		if (avatar == null && contact.getAvatar() != null) {
-			avatar = mXmppConnectionService.getFileBackend().getAvatar(contact.getAvatar(), size);
+			avatar = AvatarUtil.getAvatar(contact.getAvatar(), size);
 		}
 		if (avatar == null) {
             avatar = get(contact.getDisplayName(), size, cachedOnly);
 		}
-		this.mXmppConnectionService.getBitmapCache().put(KEY, avatar);
+		ImageUtil.addBitmapToCache(KEY, avatar);
 		return avatar;
 	}
 
 	public void clear(Contact contact) {
 		synchronized (this.sizes) {
 			for (Integer size : sizes) {
-				this.mXmppConnectionService.getBitmapCache().remove(
-						key(contact, size));
+				ImageUtil.removeBitmapFromCache(key(contact, size));
 			}
 		}
 	}
@@ -117,7 +118,7 @@ public class AvatarService {
 
 	private Bitmap get(MucOptions mucOptions, int size,  boolean cachedOnly) {
 		final String KEY = key(mucOptions, size);
-		Bitmap bitmap = this.mXmppConnectionService.getBitmapCache().get(KEY);
+		Bitmap bitmap = ImageUtil.getBitmapFromCache(KEY);
 		if (bitmap != null || cachedOnly) {
 			return bitmap;
 		}
@@ -155,15 +156,14 @@ public class AvatarService {
 			drawTile(canvas, "\u2026", PLACEHOLDER_COLOR, size / 2 + 1, size / 2 + 1,
 					size, size);
 		}
-		this.mXmppConnectionService.getBitmapCache().put(KEY, bitmap);
+		ImageUtil.addBitmapToCache(KEY, bitmap);
 		return bitmap;
 	}
 
 	public void clear(MucOptions options) {
 		synchronized (this.sizes) {
 			for (Integer size : sizes) {
-				this.mXmppConnectionService.getBitmapCache().remove(
-						key(options, size));
+				ImageUtil.removeBitmapFromCache(key(options, size));
 			}
 		}
 	}
@@ -180,24 +180,22 @@ public class AvatarService {
 
 	public Bitmap get(Account account, int size) {
 		final String KEY = key(account, size);
-		Bitmap avatar = mXmppConnectionService.getBitmapCache().get(KEY);
+		Bitmap avatar = ImageUtil.getBitmapFromCache(KEY);
 		if (avatar != null) {
 			return avatar;
 		}
-		avatar = mXmppConnectionService.getFileBackend().getAvatar(
-				account.getAvatar(), size);
+		avatar = AvatarUtil.getAvatar(account.getAvatar(), size);
 		if (avatar == null) {
 			avatar = get(account.getJid().toBareJid().toString(), size,false);
 		}
-		mXmppConnectionService.getBitmapCache().put(KEY, avatar);
+		ImageUtil.addBitmapToCache(KEY, avatar);
 		return avatar;
 	}
 
 	public void clear(Account account) {
 		synchronized (this.sizes) {
 			for (Integer size : sizes) {
-				this.mXmppConnectionService.getBitmapCache().remove(
-						key(account, size));
+				ImageUtil.removeBitmapFromCache(key(account, size));
 			}
 		}
 	}
@@ -218,7 +216,7 @@ public class AvatarService {
 
 	public Bitmap get(final String name, final int size, boolean cachedOnly) {
 		final String KEY = key(name, size);
-		Bitmap bitmap = mXmppConnectionService.getBitmapCache().get(KEY);
+		Bitmap bitmap = ImageUtil.getBitmapFromCache(KEY);
 		if (bitmap != null || cachedOnly) {
 			return bitmap;
 		}
@@ -228,7 +226,7 @@ public class AvatarService {
 		final String letter = trimmedName.isEmpty() ? "X" : trimmedName.substring(0,1);
 		final int color = UIHelper.getColorForName(name);
 		drawTile(canvas, letter, color, 0, 0, size, size);
-		mXmppConnectionService.getBitmapCache().put(KEY, bitmap);
+		ImageUtil.addBitmapToCache(KEY, bitmap);
 		return bitmap;
 	}
 
@@ -268,12 +266,10 @@ public class AvatarService {
 			if (contact.getProfilePhoto() != null) {
 				uri = Uri.parse(contact.getProfilePhoto());
 			} else if (contact.getAvatar() != null) {
-				uri = mXmppConnectionService.getFileBackend().getAvatarUri(
-						contact.getAvatar());
+				uri = AvatarUtil.getAvatarUri(contact.getAvatar());
 			}
 			if (uri != null) {
-				Bitmap bitmap = mXmppConnectionService.getFileBackend()
-						.cropCenter(uri, bottom - top, right - left);
+				Bitmap bitmap = ImageUtil.cropCenter(uri, bottom - top, right - left);
 				if (bitmap != null) {
 					drawTile(canvas, bitmap, left, top, right, bottom);
 					return;
diff --git a/src/main/java/de/thedevstack/conversationsplus/services/NotificationService.java b/src/main/java/de/thedevstack/conversationsplus/services/NotificationService.java
index 1536e8b1..dd448360 100644
--- a/src/main/java/de/thedevstack/conversationsplus/services/NotificationService.java
+++ b/src/main/java/de/thedevstack/conversationsplus/services/NotificationService.java
@@ -32,6 +32,7 @@ import java.util.regex.Pattern;
 
 import de.thedevstack.conversationsplus.ConversationsPlusApplication;
 import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
+import de.thedevstack.conversationsplus.utils.ImageUtil;
 import de.tzur.conversations.Settings;
 import de.thedevstack.conversationsplus.Config;
 import de.thedevstack.conversationsplus.R;
@@ -286,8 +287,7 @@ public class NotificationService {
 	private void modifyForImage(final Builder builder, final Message message,
 			final ArrayList<Message> messages, final boolean notify) {
 		try {
-			final Bitmap bitmap = mXmppConnectionService.getFileBackend()
-				.getThumbnail(message, getPixel(288), false);
+			final Bitmap bitmap = ImageUtil.getThumbnail(message, getPixel(288), false);
 			final ArrayList<Message> tmp = new ArrayList<>();
 			for (final Message msg : messages) {
 				if (msg.getType() == Message.TYPE_TEXT
diff --git a/src/main/java/de/thedevstack/conversationsplus/services/XmppConnectionService.java b/src/main/java/de/thedevstack/conversationsplus/services/XmppConnectionService.java
index 62ed2781..624914dd 100644
--- a/src/main/java/de/thedevstack/conversationsplus/services/XmppConnectionService.java
+++ b/src/main/java/de/thedevstack/conversationsplus/services/XmppConnectionService.java
@@ -1,14 +1,12 @@
 package de.thedevstack.conversationsplus.services;
 
 import android.annotation.SuppressLint;
-import android.app.Activity;
 import android.app.AlarmManager;
 import android.app.PendingIntent;
 import android.app.Service;
 import android.content.Context;
 import android.content.Intent;
 import android.database.ContentObserver;
-import android.database.Cursor;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.net.ConnectivityManager;
@@ -23,9 +21,7 @@ import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
 import android.os.SystemClock;
 import android.provider.ContactsContract;
-import android.provider.MediaStore;
 import android.util.Log;
-import android.util.LruCache;
 
 import net.java.otr4j.OtrException;
 import net.java.otr4j.session.Session;
@@ -36,7 +32,6 @@ import net.java.otr4j.session.SessionStatus;
 import org.openintents.openpgp.util.OpenPgpApi;
 import org.openintents.openpgp.util.OpenPgpServiceConnection;
 
-import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -57,10 +52,10 @@ import java.util.concurrent.CopyOnWriteArrayList;
 import de.duenndns.ssl.MemorizingTrustManager;
 import de.thedevstack.conversationsplus.ConversationsPlusApplication;
 import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
-import de.thedevstack.conversationsplus.enums.UserDecision;
-import de.thedevstack.conversationsplus.ui.dialogs.UserDecisionDialog;
-import de.thedevstack.conversationsplus.ui.listeners.ResizePictureUserDecisionListener;
+import de.thedevstack.conversationsplus.exceptions.FileCopyException;
+import de.thedevstack.conversationsplus.utils.AvatarUtil;
 import de.thedevstack.conversationsplus.utils.FileHelper;
+import de.thedevstack.conversationsplus.utils.ImageUtil;
 import de.tzur.conversations.Settings;
 import de.thedevstack.conversationsplus.Config;
 import de.thedevstack.conversationsplus.R;
@@ -215,7 +210,6 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 			}
 		}
 	};
-	private FileBackend fileBackend = new FileBackend(this);
 	private MemorizingTrustManager mMemorizingTrustManager;
 	private NotificationService mNotificationService = new NotificationService(
 			this);
@@ -322,7 +316,6 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 	private PgpEngine mPgpEngine = null;
 	private WakeLock wakeLock;
 	private PowerManager pm;
-	private LruCache<String, Bitmap> mBitmapCache;
 	private Thread mPhoneContactMergerThread;
 
 	private boolean mRestoredFromDatabase = false;
@@ -344,10 +337,6 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 
 	}
 
-	public FileBackend getFileBackend() {
-		return this.fileBackend;
-	}
-
 	public AvatarService getAvatarService() {
 		return this.mAvatarService;
 	}
@@ -384,10 +373,10 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 		}
 		message.setCounterpart(conversation.getNextCounterpart());
 		message.setType(Message.TYPE_FILE);
-		String path = getFileBackend().getOriginalPath(uri);
+		String path = FileHelper.getRealPathFromUri(uri);
 		if (path!=null) {
 			message.setRelativeFilePath(path);
-			getFileBackend().updateFileParams(message);
+			FileBackend.updateFileParams(message);
 			if (message.getEncryption() == Message.ENCRYPTION_DECRYPTED) {
 				getPgpEngine().encrypt(message, callback);
 			} else {
@@ -395,21 +384,21 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 			}
 		} else {
 			mFileAddingExecutor.execute(new Runnable() {
-                @Override
-                public void run() {
-                    try {
-                        getFileBackend().copyFileToPrivateStorage(message, uri);
-                        getFileBackend().updateFileParams(message);
-                        if (message.getEncryption() == Message.ENCRYPTION_DECRYPTED) {
-                            getPgpEngine().encrypt(message, callback);
-                        } else {
-                            callback.success(message);
-                        }
-                    } catch (FileBackend.FileCopyException e) {
-                        callback.error(e.getResId(), message);
-                    }
-                }
-            });
+				@Override
+				public void run() {
+					try {
+						FileBackend.copyFileToPrivateStorage(message, uri);
+						FileBackend.updateFileParams(message);
+						if (message.getEncryption() == Message.ENCRYPTION_DECRYPTED) {
+							getPgpEngine().encrypt(message, callback);
+						} else {
+							callback.success(message);
+						}
+					} catch (FileCopyException e) {
+						callback.error(e.getResId(), message);
+					}
+				}
+			});
 		}
 	}
 
@@ -477,13 +466,13 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
             @Override
             public void run() {
                 try {
-                    getFileBackend().copyImageToPrivateStorage(message, uri);
+                    FileBackend.copyImageToPrivateStorage(message, uri);
                     if (conversation.getNextEncryption(forceEncryption) == Message.ENCRYPTION_PGP) {
                         getPgpEngine().encrypt(message, callback);
                     } else {
                         callback.success(message);
                     }
-                } catch (final FileBackend.FileCopyException e) {
+                } catch (final FileCopyException e) {
                     callback.error(e.getResId(), message);
                 }
             }
@@ -659,14 +648,6 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 		PRNGFixes.apply();
 		this.mRandom = new SecureRandom();
 		updateMemorizingTrustmanager();
-		final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
-		final int cacheSize = maxMemory / 8;
-		this.mBitmapCache = new LruCache<String, Bitmap>(cacheSize) {
-			@Override
-			protected int sizeOf(final String key, final Bitmap bitmap) {
-				return bitmap.getByteCount() / 1024;
-			}
-		};
 
 		this.databaseBackend = DatabaseBackend.getInstance(getApplicationContext());
 		this.accounts = databaseBackend.getAccounts();
@@ -908,7 +889,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 		} else {
 			Log.d(Config.LOGTAG, account.getJid().toBareJid() + ": fetching roster");
 		}
-		iqPacket.query(Xmlns.ROSTER).setAttribute("ver",account.getRosterVersion());
+		iqPacket.query(Xmlns.ROSTER).setAttribute("ver", account.getRosterVersion());
 		sendIqPacket(account, iqPacket, mIqParser);
 	}
 
@@ -1022,7 +1003,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 					for(Account account : accounts) {
 						databaseBackend.readRoster(account.getRoster());
 					}
-					getBitmapCache().evictAll();
+					ImageUtil.evictBitmapCache();
 					Looper.prepare();
 					PhoneHelper.loadPhoneContacts(getApplicationContext(),
 							new CopyOnWriteArrayList<Bundle>(),
@@ -1050,7 +1031,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 
 			@Override
 			public void onMessageFound(Message message) {
-				if (!getFileBackend().isFileAvailable(message)) {
+				if (!FileBackend.isFileAvailable(message)) {
 					message.setTransferable(new TransferablePlaceholder(Transferable.STATUS_DELETED));
 				}
 			}
@@ -1061,7 +1042,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 		for (Conversation conversation : getConversations()) {
 			Message message = conversation.findMessageWithFileAndUuid(uuid);
 			if (message != null) {
-				if (!getFileBackend().isFileAvailable(message)) {
+				if (!FileBackend.isFileAvailable(message)) {
 					message.setTransferable(new TransferablePlaceholder(Transferable.STATUS_DELETED));
 					updateConversationUi();
 				}
@@ -1087,19 +1068,19 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 			}
 		}
 		Collections.sort(list, new Comparator<Conversation>() {
-            @Override
-            public int compare(Conversation lhs, Conversation rhs) {
-                Message left = lhs.getLatestMessage();
-                Message right = rhs.getLatestMessage();
-                if (left.getTimeSent() > right.getTimeSent()) {
-                    return -1;
-                } else if (left.getTimeSent() < right.getTimeSent()) {
-                    return 1;
-                } else {
-                    return 0;
-                }
-            }
-        });
+			@Override
+			public int compare(Conversation lhs, Conversation rhs) {
+				Message left = lhs.getLatestMessage();
+				Message right = rhs.getLatestMessage();
+				if (left.getTimeSent() > right.getTimeSent()) {
+					return -1;
+				} else if (left.getTimeSent() < right.getTimeSent()) {
+					return 1;
+				} else {
+					return 0;
+				}
+			}
+		});
 	}
 
 	public void loadMoreMessages(final Conversation conversation, final long timestamp, final OnMoreMessagesLoaded callback) {
@@ -1271,17 +1252,17 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 	public void updateAccountPasswordOnServer(final Account account, final String newPassword, final OnAccountPasswordChanged callback) {
 		final IqPacket iq = getIqGenerator().generateSetPassword(account, newPassword);
 		sendIqPacket(account, iq, new OnIqPacketReceived() {
-            @Override
-            public void onIqPacketReceived(final Account account, final IqPacket packet) {
-                if (packet.getType() == IqPacket.TYPE.RESULT) {
-                    account.setPassword(newPassword);
-                    databaseBackend.updateAccount(account);
-                    callback.onPasswordChangeSucceeded();
-                } else {
-                    callback.onPasswordChangeFailed();
-                }
-            }
-        });
+			@Override
+			public void onIqPacketReceived(final Account account, final IqPacket packet) {
+				if (packet.getType() == IqPacket.TYPE.RESULT) {
+					account.setPassword(newPassword);
+					databaseBackend.updateAccount(account);
+					callback.onPasswordChangeSucceeded();
+				} else {
+					callback.onPasswordChangeFailed();
+				}
+			}
+		});
 	}
 
 	public void deleteAccount(final Account account) {
@@ -1616,7 +1597,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 			conversation.getMucOptions().setOffline();
 			conversation.deregisterWithBookmark();
 			Log.d(Config.LOGTAG, conversation.getAccount().getJid().toBareJid()
-                    + ": leaving muc " + conversation.getJid());
+					+ ": leaving muc " + conversation.getJid());
 		} else {
 			account.pendingConferenceLeaves.add(conversation);
 		}
@@ -1700,23 +1681,23 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 		request.setTo(conversation.getJid().toBareJid());
 		request.query("http://jabber.org/protocol/disco#info");
 		sendIqPacket(conversation.getAccount(), request, new OnIqPacketReceived() {
-            @Override
-            public void onIqPacketReceived(Account account, IqPacket packet) {
-                if (packet.getType() != IqPacket.TYPE.ERROR) {
-                    ArrayList<String> features = new ArrayList<>();
-                    for (Element child : packet.query().getChildren()) {
-                        if (child != null && child.getName().equals("feature")) {
-                            String var = child.getAttribute("var");
-                            if (var != null) {
-                                features.add(var);
-                            }
-                        }
-                    }
-                    conversation.getMucOptions().updateFeatures(features);
-                    updateConversationUi();
-                }
-            }
-        });
+			@Override
+			public void onIqPacketReceived(Account account, IqPacket packet) {
+				if (packet.getType() != IqPacket.TYPE.ERROR) {
+					ArrayList<String> features = new ArrayList<>();
+					for (Element child : packet.query().getChildren()) {
+						if (child != null && child.getName().equals("feature")) {
+							String var = child.getAttribute("var");
+							if (var != null) {
+								features.add(var);
+							}
+						}
+					}
+					conversation.getMucOptions().updateFeatures(features);
+					updateConversationUi();
+				}
+			}
+		});
 	}
 
 	public void pushConferenceConfiguration(final Conversation conversation, final Bundle options, final OnConferenceOptionsPushed callback) {
@@ -1876,27 +1857,27 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 						+ otrSession.getSessionID().getUserID());
 		conversation.findUnsentMessagesWithOtrEncryption(new Conversation.OnMessageFound() {
 
-            @Override
-            public void onMessageFound(Message message) {
-                SessionID id = otrSession.getSessionID();
-                try {
-                    message.setCounterpart(Jid.fromString(id.getAccountID() + "/" + id.getUserID()));
-                } catch (InvalidJidException e) {
-                    return;
-                }
-                if (message.needsUploading()) {
-                    mJingleConnectionManager.createNewConnection(message);
-                } else {
-                    MessagePacket outPacket = mMessageGenerator.generateOtrChat(message, true);
-                    if (outPacket != null) {
-                        message.setStatus(Message.STATUS_SEND);
-                        databaseBackend.updateMessage(message);
-                        sendMessagePacket(account, outPacket);
-                    }
-                }
-                updateConversationUi();
-            }
-        });
+			@Override
+			public void onMessageFound(Message message) {
+				SessionID id = otrSession.getSessionID();
+				try {
+					message.setCounterpart(Jid.fromString(id.getAccountID() + "/" + id.getUserID()));
+				} catch (InvalidJidException e) {
+					return;
+				}
+				if (message.needsUploading()) {
+					mJingleConnectionManager.createNewConnection(message);
+				} else {
+					MessagePacket outPacket = mMessageGenerator.generateOtrChat(message, true);
+					if (outPacket != null) {
+						message.setStatus(Message.STATUS_SEND);
+						databaseBackend.updateMessage(message);
+						sendMessagePacket(account, outPacket);
+					}
+				}
+				updateConversationUi();
+			}
+		});
 	}
 
 	public boolean renewSymmetricKey(Conversation conversation) {
@@ -1954,8 +1935,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 							  final UiCallback<Avatar> callback) {
 		final Bitmap.CompressFormat format = Config.AVATAR_FORMAT;
 		final int size = Config.AVATAR_SIZE;
-		final Avatar avatar = getFileBackend()
-				.getPepAvatar(image, size, format);
+		final Avatar avatar = AvatarUtil.getPepAvatar(image, size, format);
 		if (avatar != null) {
 			avatar.height = size;
 			avatar.width = size;
@@ -1966,7 +1946,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 			} else if (format.equals(Bitmap.CompressFormat.PNG)) {
 				avatar.type = "image/png";
 			}
-			if (!getFileBackend().save(avatar)) {
+			if (!AvatarUtil.save(avatar)) {
 				callback.error(R.string.error_saving_avatar, avatar);
 				return;
 			}
@@ -2050,7 +2030,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 				if (result.getType() == IqPacket.TYPE.RESULT) {
 					avatar.image = mIqParser.avatarData(result);
 					if (avatar.image != null) {
-						if (getFileBackend().save(avatar)) {
+						if (AvatarUtil.save(avatar)) {
 							if (account.getJid().toBareJid().equals(avatar.owner)) {
 								if (account.setAvatar(avatar.getFilename())) {
 									databaseBackend.updateAccount(account);
@@ -2096,31 +2076,31 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 	private void fetchAvatarVcard(final Account account, final Avatar avatar, final UiCallback<Avatar> callback) {
 		IqPacket packet = this.mIqGenerator.retrieveVcardAvatar(avatar);
 		this.sendIqPacket(account, packet, new OnIqPacketReceived() {
-            @Override
-            public void onIqPacketReceived(Account account, IqPacket packet) {
-                synchronized (mInProgressAvatarFetches) {
-                    mInProgressAvatarFetches.remove(generateFetchKey(account, avatar));
-                }
-                if (packet.getType() == IqPacket.TYPE.RESULT) {
-                    Element vCard = packet.findChild("vCard", "vcard-temp");
-                    Element photo = vCard != null ? vCard.findChild("PHOTO") : null;
-                    String image = photo != null ? photo.findChildContent("BINVAL") : null;
-                    if (image != null) {
-                        avatar.image = image;
-                        if (getFileBackend().save(avatar)) {
-                            Log.d(Config.LOGTAG, account.getJid().toBareJid()
-                                    + ": successfully fetched vCard avatar for " + avatar.owner);
-                            Contact contact = account.getRoster()
-                                    .getContact(avatar.owner);
-                            contact.setAvatar(avatar);
-                            getAvatarService().clear(contact);
-                            updateConversationUi();
-                            updateRosterUi();
-                        }
-                    }
-                }
-            }
-        });
+			@Override
+			public void onIqPacketReceived(Account account, IqPacket packet) {
+				synchronized (mInProgressAvatarFetches) {
+					mInProgressAvatarFetches.remove(generateFetchKey(account, avatar));
+				}
+				if (packet.getType() == IqPacket.TYPE.RESULT) {
+					Element vCard = packet.findChild("vCard", "vcard-temp");
+					Element photo = vCard != null ? vCard.findChild("PHOTO") : null;
+					String image = photo != null ? photo.findChildContent("BINVAL") : null;
+					if (image != null) {
+						avatar.image = image;
+						if (AvatarUtil.save(avatar)) {
+							Log.d(Config.LOGTAG, account.getJid().toBareJid()
+									+ ": successfully fetched vCard avatar for " + avatar.owner);
+							Contact contact = account.getRoster()
+									.getContact(avatar.owner);
+							contact.setAvatar(avatar);
+							getAvatarService().clear(contact);
+							updateConversationUi();
+							updateRosterUi();
+						}
+					}
+				}
+			}
+		});
 	}
 
 	public void checkForAvatar(Account account, final UiCallback<Avatar> callback) {
@@ -2138,7 +2118,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 							Avatar avatar = Avatar.parseMetadata(items);
 							if (avatar != null) {
 								avatar.owner = account.getJid().toBareJid();
-								if (fileBackend.isAvatarCached(avatar)) {
+								if (AvatarUtil.isAvatarCached(avatar)) {
 									if (account.setAvatar(avatar.getFilename())) {
 										databaseBackend.updateAccount(account);
 									}
@@ -2401,10 +2381,6 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
 		return this.pm;
 	}
 
-	public LruCache<String, Bitmap> getBitmapCache() {
-		return this.mBitmapCache;
-	}
-
 	public void syncRosterToDisk(final Account account) {
 		Runnable runnable = new Runnable() {
 
diff --git a/src/main/java/de/thedevstack/conversationsplus/ui/ConversationActivity.java b/src/main/java/de/thedevstack/conversationsplus/ui/ConversationActivity.java
index 3ae2a07a..94d1e2ea 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ui/ConversationActivity.java
+++ b/src/main/java/de/thedevstack/conversationsplus/ui/ConversationActivity.java
@@ -30,6 +30,7 @@ import android.widget.Toast;
 import net.java.otr4j.session.SessionStatus;
 
 import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.ui.dialogs.UserDecisionDialog;
 import de.thedevstack.conversationsplus.ui.listeners.ResizePictureUserDecisionListener;
 import de.timroes.android.listview.EnhancedListView;
@@ -424,7 +425,7 @@ public class ConversationActivity extends XmppActivity
 						chooser = true;
 						break;
 					case ATTACHMENT_CHOICE_TAKE_PHOTO:
-						Uri uri = xmppConnectionService.getFileBackend().getTakePhotoUri();
+						Uri uri = FileBackend.getTakePhotoUri();
 						intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
 						intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
 						mPendingImageUris.clear();
diff --git a/src/main/java/de/thedevstack/conversationsplus/ui/ConversationFragment.java b/src/main/java/de/thedevstack/conversationsplus/ui/ConversationFragment.java
index 3fbe59f4..94cb896b 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ui/ConversationFragment.java
+++ b/src/main/java/de/thedevstack/conversationsplus/ui/ConversationFragment.java
@@ -42,6 +42,7 @@ import java.util.NoSuchElementException;
 import java.util.concurrent.ConcurrentLinkedQueue;
 
 import de.thedevstack.conversationsplus.ConversationsPlusPreferences;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.ui.dialogs.MessageDetailsDialog;
 import de.thedevstack.conversationsplus.ui.listeners.ConversationSwipeRefreshListener;
 import de.thedevstack.conversationsplus.Config;
@@ -535,9 +536,7 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 			shareIntent.putExtra(Intent.EXTRA_TEXT, message.getBody());
 			shareIntent.setType("text/plain");
 		} else {
-			shareIntent.putExtra(Intent.EXTRA_STREAM,
-					activity.xmppConnectionService.getFileBackend()
-							.getJingleFileUri(message));
+			shareIntent.putExtra(Intent.EXTRA_STREAM, FileBackend.getJingleFileUri(message));
 			shareIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 			String mime = message.getMimeType();
 			if (mime == null) {
@@ -563,7 +562,7 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 
 	private void resendMessage(Message message) {
 		if (message.getType() == Message.TYPE_FILE || message.getType() == Message.TYPE_IMAGE) {
-			DownloadableFile file = activity.xmppConnectionService.getFileBackend().getFile(message);
+			DownloadableFile file = FileBackend.getFile(message);
 			if (!file.exists()) {
 				Toast.makeText(activity, R.string.file_deleted, Toast.LENGTH_SHORT).show();
 				message.setTransferable(new TransferablePlaceholder(Transferable.STATUS_DELETED));
diff --git a/src/main/java/de/thedevstack/conversationsplus/ui/PublishProfilePictureActivity.java b/src/main/java/de/thedevstack/conversationsplus/ui/PublishProfilePictureActivity.java
index be08da14..966cc379 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ui/PublishProfilePictureActivity.java
+++ b/src/main/java/de/thedevstack/conversationsplus/ui/PublishProfilePictureActivity.java
@@ -15,6 +15,7 @@ import android.widget.Toast;
 
 import de.thedevstack.conversationsplus.R;
 import de.thedevstack.conversationsplus.entities.Account;
+import de.thedevstack.conversationsplus.utils.ImageUtil;
 import de.thedevstack.conversationsplus.utils.PhoneHelper;
 import de.thedevstack.conversationsplus.xmpp.jid.InvalidJidException;
 import de.thedevstack.conversationsplus.xmpp.jid.Jid;
@@ -211,8 +212,7 @@ public class PublishProfilePictureActivity extends XmppActivity {
 	}
 
 	protected void loadImageIntoPreview(Uri uri) {
-		Bitmap bm = xmppConnectionService.getFileBackend().cropCenterSquare(
-				uri, 384);
+		Bitmap bm = ImageUtil.cropCenterSquare(uri, 384);
 		if (bm == null) {
 			disablePublishButton();
 			this.hintOrWarning.setTextColor(getWarningTextColor());
diff --git a/src/main/java/de/thedevstack/conversationsplus/ui/XmppActivity.java b/src/main/java/de/thedevstack/conversationsplus/ui/XmppActivity.java
index ecf1ce77..97582fc7 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ui/XmppActivity.java
+++ b/src/main/java/de/thedevstack/conversationsplus/ui/XmppActivity.java
@@ -56,7 +56,6 @@ import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
 import net.java.otr4j.session.SessionID;
 
 import java.io.FileNotFoundException;
-import java.io.IOException;
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Hashtable;
@@ -76,6 +75,7 @@ import de.thedevstack.conversationsplus.services.AvatarService;
 import de.thedevstack.conversationsplus.services.XmppConnectionService;
 import de.thedevstack.conversationsplus.services.XmppConnectionService.XmppConnectionBinder;
 import de.thedevstack.conversationsplus.utils.ExceptionHelper;
+import de.thedevstack.conversationsplus.utils.ImageUtil;
 import de.thedevstack.conversationsplus.xmpp.OnUpdateBlocklist;
 import de.thedevstack.conversationsplus.xmpp.jid.InvalidJidException;
 import de.thedevstack.conversationsplus.xmpp.jid.Jid;
@@ -881,8 +881,7 @@ public abstract class XmppActivity extends Activity {
 		protected Bitmap doInBackground(Message... params) {
 			message = params[0];
 			try {
-				return xmppConnectionService.getFileBackend().getThumbnail(
-						message, (int) (metrics.density * 288), false);
+				return ImageUtil.getThumbnail(message, (int) (metrics.density * 288), false);
 			} catch (FileNotFoundException e) {
 				return null;
 			}
@@ -907,8 +906,7 @@ public abstract class XmppActivity extends Activity {
 	public void loadBitmap(Message message, ImageView imageView, boolean setSize) {
 		Bitmap bm;
 		try {
-			bm = xmppConnectionService.getFileBackend().getThumbnail(message,
-					(int) (metrics.density * 288), true);
+			bm = ImageUtil.getThumbnail(message,(int) (metrics.density * 288), true);
 		} catch (FileNotFoundException e) {
 			bm = null;
 		}
diff --git a/src/main/java/de/thedevstack/conversationsplus/ui/adapter/MessageAdapter.java b/src/main/java/de/thedevstack/conversationsplus/ui/adapter/MessageAdapter.java
index bbe0d362..9ab7abf0 100644
--- a/src/main/java/de/thedevstack/conversationsplus/ui/adapter/MessageAdapter.java
+++ b/src/main/java/de/thedevstack/conversationsplus/ui/adapter/MessageAdapter.java
@@ -11,7 +11,6 @@ import android.text.Spanned;
 import android.text.style.ForegroundColorSpan;
 import android.text.style.RelativeSizeSpan;
 import android.text.style.StyleSpan;
-import android.util.DisplayMetrics;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.View.OnLongClickListener;
@@ -34,6 +33,7 @@ import de.thedevstack.conversationsplus.entities.Transferable;
 import de.thedevstack.conversationsplus.entities.DownloadableFile;
 import de.thedevstack.conversationsplus.entities.Message;
 import de.thedevstack.conversationsplus.entities.Message.FileParams;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.ui.ConversationActivity;
 import de.thedevstack.conversationsplus.utils.GeoHelper;
 import de.thedevstack.conversationsplus.utils.UIHelper;
@@ -47,8 +47,6 @@ public class MessageAdapter extends ArrayAdapter<Message> {
 
 	private ConversationActivity activity;
 
-	private DisplayMetrics metrics;
-
 	private OnContactPictureClicked mOnContactPictureClickedListener;
 	private OnContactPictureLongClicked mOnContactPictureLongClickedListener;
 
@@ -64,7 +62,6 @@ public class MessageAdapter extends ArrayAdapter<Message> {
 	public MessageAdapter(ConversationActivity activity, List<Message> messages) {
 		super(activity, 0, messages);
 		this.activity = activity;
-		metrics = getContext().getResources().getDisplayMetrics();
 	}
 
 	public void setOnContactPictureClicked(OnContactPictureClicked listener) {
@@ -363,8 +360,7 @@ public class MessageAdapter extends ArrayAdapter<Message> {
             @Override
             public void onClick(View v) {
                 Intent intent = new Intent(Intent.ACTION_VIEW);
-                intent.setDataAndType(activity.xmppConnectionService
-                        .getFileBackend().getJingleFileUri(message), "image/*");
+                intent.setDataAndType(FileBackend.getJingleFileUri(message), "image/*");
                 getContext().startActivity(intent);
             }
         });
@@ -551,7 +547,7 @@ public class MessageAdapter extends ArrayAdapter<Message> {
 	}
 
 	public void openDownloadable(Message message) {
-		DownloadableFile file = activity.xmppConnectionService.getFileBackend().getFile(message);
+		DownloadableFile file = FileBackend.getFile(message);
 		if (!file.exists()) {
 			Toast.makeText(activity,R.string.file_deleted,Toast.LENGTH_SHORT).show();
 			return;
diff --git a/src/main/java/de/thedevstack/conversationsplus/utils/AvatarUtil.java b/src/main/java/de/thedevstack/conversationsplus/utils/AvatarUtil.java
new file mode 100644
index 00000000..287f4b50
--- /dev/null
+++ b/src/main/java/de/thedevstack/conversationsplus/utils/AvatarUtil.java
@@ -0,0 +1,162 @@
+package de.thedevstack.conversationsplus.utils;
+
+import android.graphics.Bitmap;
+import android.net.Uri;
+import android.util.Base64;
+import android.util.Base64OutputStream;
+import android.util.Log;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.security.DigestOutputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import de.thedevstack.conversationsplus.Config;
+import de.thedevstack.conversationsplus.ConversationsPlusApplication;
+import de.thedevstack.conversationsplus.xmpp.pep.Avatar;
+
+/**
+ * This util provides access to saved avatars, creating avatars.
+ */
+public final class AvatarUtil {
+
+    /**
+     * Get the PEP Avatar.
+     * TODO: Why PEP Avatar?
+     * @param image the uri to the avatar's image
+     * @param size the image width/height to resize to
+     * @param format the format for the avatar
+     * @return the avatar
+     */
+    public static Avatar getPepAvatar(Uri image, int size, Bitmap.CompressFormat format) {
+        try {
+            Avatar avatar = new Avatar();
+            Bitmap bm = ImageUtil.cropCenterSquare(image, size);
+            if (bm == null) {
+                return null;
+            }
+            ByteArrayOutputStream mByteArrayOutputStream = new ByteArrayOutputStream();
+            Base64OutputStream mBase64OutputSttream = new Base64OutputStream(
+                    mByteArrayOutputStream, Base64.DEFAULT);
+            MessageDigest digest = MessageDigest.getInstance("SHA-1");
+            DigestOutputStream mDigestOutputStream = new DigestOutputStream(
+                    mBase64OutputSttream, digest);
+            if (!bm.compress(format, 75, mDigestOutputStream)) {
+                return null;
+            }
+            mDigestOutputStream.flush();
+            mDigestOutputStream.close();
+            avatar.sha1sum = CryptoHelper.bytesToHex(digest.digest());
+            avatar.image = new String(mByteArrayOutputStream.toByteArray());
+            return avatar;
+        } catch (NoSuchAlgorithmException e) {
+            return null;
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Returns whether the avatar is cached or not.
+     * @param avatar the avatar to check the existance
+     * @return <code>true</code> if the file of the avatar exists, <code>false</code> otherwise
+     */
+    public static boolean isAvatarCached(Avatar avatar) {
+        File file = new File(getAvatarPath(avatar.getFilename()));
+        return file.exists();
+    }
+
+    /**
+     * Saves an avatar to the file system.
+     * All exceptions are silently ignored.
+     * TODO: Move real saving operation to FileBackend
+     * @param avatar the avatar to save
+     * @return <code>true</code> if the avatar was saved successfully, <code>false</code> otherwise.
+     */
+    public static boolean save(Avatar avatar) {
+        File file;
+        if (isAvatarCached(avatar)) {
+            file = new File(getAvatarPath(avatar.getFilename()));
+        } else {
+            String filename = getAvatarPath(avatar.getFilename());
+            file = new File(filename + ".tmp");
+            file.getParentFile().mkdirs();
+            OutputStream os = null;
+            try {
+                file.createNewFile();
+                os = new FileOutputStream(file);
+                MessageDigest digest = MessageDigest.getInstance("SHA-1");
+                digest.reset();
+                DigestOutputStream mDigestOutputStream = new DigestOutputStream(os, digest);
+                mDigestOutputStream.write(avatar.getImageAsBytes());
+                mDigestOutputStream.flush();
+                mDigestOutputStream.close();
+                String sha1sum = CryptoHelper.bytesToHex(digest.digest());
+                if (sha1sum.equals(avatar.sha1sum)) {
+                    file.renameTo(new File(filename));
+                } else {
+                    Log.d(Config.LOGTAG, "sha1sum mismatch for " + avatar.owner);
+                    file.delete();
+                    return false;
+                }
+            } catch (FileNotFoundException e) {
+                return false;
+            } catch (IOException e) {
+                return false;
+            } catch (NoSuchAlgorithmException e) {
+                return false;
+            } finally {
+                StreamUtil.close(os);
+            }
+        }
+        avatar.size = file.length();
+        return true;
+    }
+
+    /**
+     * Returns the avatar for an uri.
+     * @param avatar the avatar's uri
+     * @param size the height/width the avatar should have
+     * @return the bitmap of the uri
+     */
+    public static Bitmap getAvatar(String avatar, int size) {
+        if (avatar == null) {
+            return null;
+        }
+        Bitmap bm = ImageUtil.cropCenter(getAvatarUri(avatar), size, size);
+        if (bm == null) {
+            return null;
+        }
+        return bm;
+    }
+
+    /**
+     * Returns the path to an avatar
+     * @param avatar the name of the avatar.
+     * @return the path as string
+     */
+    public static String getAvatarPath(String avatar) {
+        return ConversationsPlusApplication.getInstance().getFilesDir().getAbsolutePath()+ "/avatars/" + avatar;
+    }
+
+    /**
+     * Returns the path to an avatar as an uri.
+     * @param avatar the name of the avatar
+     * @return the path as uri
+     */
+    public static Uri getAvatarUri(String avatar) {
+        return Uri.parse("file:" + getAvatarPath(avatar));
+    }
+
+    /**
+     * Avoid instantiation it's an helper class.
+     */
+    private AvatarUtil() {
+        // Static helper class
+    }
+}
diff --git a/src/main/java/de/thedevstack/conversationsplus/utils/ImageUtil.java b/src/main/java/de/thedevstack/conversationsplus/utils/ImageUtil.java
new file mode 100644
index 00000000..3c3e1c99
--- /dev/null
+++ b/src/main/java/de/thedevstack/conversationsplus/utils/ImageUtil.java
@@ -0,0 +1,313 @@
+package de.thedevstack.conversationsplus.utils;
+
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.graphics.Matrix;
+import android.graphics.RectF;
+import android.media.ExifInterface;
+import android.net.Uri;
+import android.util.Log;
+import android.util.LruCache;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+
+import de.thedevstack.conversationsplus.entities.Message;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
+
+/**
+ * This util provides
+ */
+public final class ImageUtil {
+    private static LruCache<String, Bitmap> BITMAP_CACHE;
+
+    /**
+     * Returns a bitmap from the cache.
+     * @see LruCache#get(Object) for details
+     * @param key the key of the bitmap to get
+     * @return the bitmap
+     */
+    public static Bitmap getBitmapFromCache(String key) {
+        return BITMAP_CACHE.get(key);
+    }
+
+    /**
+     * Adds a bitmap with the given key to the cache.
+     * @see LruCache#put(Object, Object) for details
+     * @param key the key to identify this bitmap
+     * @param bitmap the bitmap to cache
+     */
+    public static void addBitmapToCache(String key, Bitmap bitmap) {
+        BITMAP_CACHE.put(key, bitmap);
+    }
+
+    /**
+     * Removes the bitmap with given key from the cache.
+     * @param key the key of the bitmap to remove
+     */
+    public static void removeBitmapFromCache(String key) {
+        BITMAP_CACHE.remove(key);
+    }
+
+    /**
+     * Clears the cache.
+     * @see LruCache#evictAll() for more details.
+     */
+    public static void evictBitmapCache() {
+        BITMAP_CACHE.evictAll();
+    }
+
+    /**
+     * Initializes the bitmap cache.
+     * This has to be executed once on application start.
+     * @see LruCache#LruCache(int) for details
+     */
+    public static void initBitmapCache() {
+        Log.i("Conversations+ImageUtil", "Initializing BitmapCache");
+        final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
+        final int cacheSize = maxMemory / 8;
+        BITMAP_CACHE = new LruCache<String, Bitmap>(cacheSize) {
+            @Override
+            protected int sizeOf(final String key, final Bitmap bitmap) {
+                return bitmap.getByteCount() / 1024;
+            }
+        };
+    }
+
+    /**
+     * Resizes a given bitmap and return a new and resized bitmap.
+     * The bitmap is only resized if either the width or the height of the original bitmap is smaller than the given size.
+     * @param originalBitmap the bitmap to resize
+     * @param size the size to scale to
+     * @return new and resized bitmap or the original bitmap if width and height are smaller than size
+     */
+    public static Bitmap resize(Bitmap originalBitmap, int size) {
+        int w = originalBitmap.getWidth();
+        int h = originalBitmap.getHeight();
+        if (Math.max(w, h) > size) {
+            int scalledW;
+            int scalledH;
+            if (w <= h) {
+                scalledW = (int) (w / ((double) h / size));
+                scalledH = size;
+            } else {
+                scalledW = size;
+                scalledH = (int) (h / ((double) w / size));
+            }
+            return Bitmap.createScaledBitmap(originalBitmap, scalledW, scalledH, true);
+        } else {
+            return originalBitmap;
+        }
+    }
+
+    /**
+     * Returns the rotation from the exif information of an image identified with the given uri.
+     * The orientation is retrieved by parsing the stream of the image.
+     * FileNotFoundException is silently ignored.
+     * @param image the uri of the image to get the rotation
+     * @return the rotation value for the image, <code>0</code> if the file cannot be found.
+     */
+    public static int getRotation(Uri image) {
+        InputStream is = null;
+        try {
+            is = StreamUtil.openInputStreamFromContentResolver(image);
+            return ExifHelper.getOrientation(is);
+        } catch (FileNotFoundException e) {
+            return 0;
+        } finally {
+            StreamUtil.close(is);
+        }
+    }
+
+    /**
+     * Returns a thumbnail for a bitmap in a message.
+     * @param message the message to get the thumbnail for
+     * @param size the size to resize the original image to
+     * @param cacheOnly whether only cached images should be returned or not
+     * @return the resized thumbail
+     * @throws FileNotFoundException if the original image does not exist anymore or an IOException occurs.
+     */
+    public static Bitmap getThumbnail(Message message, int size, boolean cacheOnly)
+            throws FileNotFoundException {
+        Bitmap thumbnail = ImageUtil.getBitmapFromCache(message.getUuid());
+        if ((thumbnail == null) && (!cacheOnly)) {
+            File file = FileBackend.getFile(message);
+            BitmapFactory.Options options = new BitmapFactory.Options();
+            options.inSampleSize = calcSampleSize(file, size);
+            Bitmap fullsize = BitmapFactory.decodeFile(file.getAbsolutePath(),options);
+            if (fullsize == null) {
+                throw new FileNotFoundException();
+            }
+            thumbnail = resize(fullsize, size);
+            thumbnail = rotate(thumbnail, file.getAbsolutePath());
+
+            ImageUtil.addBitmapToCache(message.getUuid(), thumbnail);
+        }
+        return thumbnail;
+    }
+
+    /**
+     * Rotates an bitmap. Only the values 90°, 180° and 270° are considered to rotate the image.
+     * The orientation information is read using the ExifInterface.
+     * @param original the original bitmap
+     * @param srcPath the path to the original bitmap (used to read the exif information)
+     * @return rotated bitmap, or original bitmap if criteria are not met
+     * @throws IOException
+     */
+    public static Bitmap rotate(Bitmap original, String srcPath) {
+        try {
+            ExifInterface exif = new ExifInterface(srcPath);
+            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);
+            int rotation = 0;
+            switch (orientation) {
+                case ExifInterface.ORIENTATION_ROTATE_90:
+                    rotation = 90;
+                    break;
+                case ExifInterface.ORIENTATION_ROTATE_180:
+                    rotation = 180;
+                    break;
+                case ExifInterface.ORIENTATION_ROTATE_270:
+                    rotation = 270;
+                    break;
+            }
+            if (rotation > 0) {
+                return rotate(original, rotation);
+            }
+        } catch (IOException e) {
+            Log.w("filebackend", "Error while rotating image, returning original (" + e.getMessage() + ")");
+        }
+        return original;
+    }
+
+    /**
+     * Rotates a bitmap with given degrees.
+     * @param bitmap the bitmap to be rotated
+     * @param degree the degrees to rotate the bitmap
+     * @return a newly created bitmap
+     */
+    public static Bitmap rotate(Bitmap bitmap, int degree) {
+        int w = bitmap.getWidth();
+        int h = bitmap.getHeight();
+        Matrix mtx = new Matrix();
+        mtx.postRotate(degree);
+        return Bitmap.createBitmap(bitmap, 0, 0, w, h, mtx, true);
+    }
+
+
+    public static Bitmap cropCenterSquare(Uri image, int size) {
+        if (image == null) {
+            return null;
+        }
+        InputStream is = null;
+        try {
+            BitmapFactory.Options options = new BitmapFactory.Options();
+            options.inSampleSize = calcSampleSize(image, size);
+            is = StreamUtil.openInputStreamFromContentResolver(image);
+            Bitmap input = BitmapFactory.decodeStream(is, null, options);
+            if (input == null) {
+                return null;
+            } else {
+                int rotation = getRotation(image);
+                if (rotation > 0) {
+                    input = rotate(input, rotation);
+                }
+                return cropCenterSquare(input, size);
+            }
+        } catch (FileNotFoundException e) {
+            return null;
+        } finally {
+            StreamUtil.close(is);
+        }
+    }
+
+    public static Bitmap cropCenter(Uri image, int newHeight, int newWidth) {
+        if (image == null) {
+            return null;
+        }
+        InputStream is = null;
+        try {
+            BitmapFactory.Options options = new BitmapFactory.Options();
+            options.inSampleSize = calcSampleSize(image,Math.max(newHeight, newWidth));
+            is = StreamUtil.openInputStreamFromContentResolver(image);
+            Bitmap source = BitmapFactory.decodeStream(is, null, options);
+            if (source == null) {
+                return null;
+            }
+            int sourceWidth = source.getWidth();
+            int sourceHeight = source.getHeight();
+            float xScale = (float) newWidth / sourceWidth;
+            float yScale = (float) newHeight / sourceHeight;
+            float scale = Math.max(xScale, yScale);
+            float scaledWidth = scale * sourceWidth;
+            float scaledHeight = scale * sourceHeight;
+            float left = (newWidth - scaledWidth) / 2;
+            float top = (newHeight - scaledHeight) / 2;
+
+            RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
+            Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, Bitmap.Config.ARGB_8888);
+            Canvas canvas = new Canvas(dest);
+            canvas.drawBitmap(source, null, targetRect, null);
+            return dest;
+        } catch (FileNotFoundException e) {
+            return null;
+        } finally {
+            StreamUtil.close(is);
+        }
+    }
+
+    public static Bitmap cropCenterSquare(Bitmap input, int size) {
+        int w = input.getWidth();
+        int h = input.getHeight();
+
+        float scale = Math.max((float) size / h, (float) size / w);
+
+        float outWidth = scale * w;
+        float outHeight = scale * h;
+        float left = (size - outWidth) / 2;
+        float top = (size - outHeight) / 2;
+        RectF target = new RectF(left, top, left + outWidth, top + outHeight);
+
+        Bitmap output = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
+        Canvas canvas = new Canvas(output);
+        canvas.drawBitmap(input, null, target, null);
+        return output;
+    }
+
+    public static int calcSampleSize(Uri image, int size) throws FileNotFoundException {
+        BitmapFactory.Options options = new BitmapFactory.Options();
+        options.inJustDecodeBounds = true;
+        BitmapFactory.decodeStream(StreamUtil.openInputStreamFromContentResolver(image), null, options);
+        return calcSampleSize(options, size);
+    }
+
+    public static int calcSampleSize(File image, int size) {
+        BitmapFactory.Options options = new BitmapFactory.Options();
+        options.inJustDecodeBounds = true;
+        BitmapFactory.decodeFile(image.getAbsolutePath(), options);
+        return calcSampleSize(options, size);
+    }
+
+    public static int calcSampleSize(BitmapFactory.Options options, int size) {
+        int height = options.outHeight;
+        int width = options.outWidth;
+        int inSampleSize = 1;
+
+        if (height > size || width > size) {
+            int halfHeight = height / 2;
+            int halfWidth = width / 2;
+
+            while ((halfHeight / inSampleSize) > size
+                    && (halfWidth / inSampleSize) > size) {
+                inSampleSize *= 2;
+            }
+        }
+        return inSampleSize;
+    }
+
+    private ImageUtil() {
+        // Static helper class
+    }
+}
diff --git a/src/main/java/de/thedevstack/conversationsplus/utils/StreamUtil.java b/src/main/java/de/thedevstack/conversationsplus/utils/StreamUtil.java
new file mode 100644
index 00000000..64f46314
--- /dev/null
+++ b/src/main/java/de/thedevstack/conversationsplus/utils/StreamUtil.java
@@ -0,0 +1,48 @@
+package de.thedevstack.conversationsplus.utils;
+
+import android.net.Uri;
+
+import java.io.Closeable;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+
+import de.thedevstack.conversationsplus.ConversationsPlusApplication;
+
+/**
+ * Util to handle streams.
+ */
+public final class StreamUtil {
+
+    /**
+     * Opens an InputStream from Uri using the ContentResolver from application.
+     * @see android.content.ContentResolver#openInputStream(Uri)
+     * @param uri the uri to open
+     * @return the InputStream for given uri
+     * @throws FileNotFoundException if the provided URI could not be opened.
+     */
+    public static InputStream openInputStreamFromContentResolver(Uri uri) throws FileNotFoundException {
+        return ConversationsPlusApplication.getInstance().getContentResolver().openInputStream(uri);
+    }
+
+    /**
+     * Closes a stream.
+     * IOException is silently ignored.
+     * @param stream the stream to close
+     */
+    public static void close(Closeable stream) {
+        if (stream != null) {
+            try {
+                stream.close();
+            } catch (IOException e) {
+            }
+        }
+    }
+
+    /**
+     * Avoid instantiation of util class.
+     */
+    private StreamUtil() {
+        // Static helper class
+    }
+}
diff --git a/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleConnection.java b/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleConnection.java
index e3dcbe6c..94a0d2d7 100644
--- a/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleConnection.java
+++ b/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleConnection.java
@@ -20,6 +20,7 @@ import de.thedevstack.conversationsplus.entities.Transferable;
 import de.thedevstack.conversationsplus.entities.DownloadableFile;
 import de.thedevstack.conversationsplus.entities.TransferablePlaceholder;
 import de.thedevstack.conversationsplus.entities.Message;
+import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.services.XmppConnectionService;
 import de.thedevstack.conversationsplus.xml.Element;
 import de.thedevstack.conversationsplus.xmpp.OnIqPacketReceived;
@@ -90,7 +91,7 @@ public class JingleConnection implements Transferable {
 					JingleConnection.this.mXmppConnectionService
 							.getNotificationService().push(message);
 				}
-				mXmppConnectionService.getFileBackend().updateFileParams(message);
+				FileBackend.updateFileParams(message);
 				mXmppConnectionService.databaseBackend.createMessage(message);
 				mXmppConnectionService.markMessage(message,
 						Message.STATUS_RECEIVED);
@@ -336,8 +337,7 @@ public class JingleConnection implements Transferable {
 					this.mXmppConnectionService.getNotificationService()
 							.push(message);
 				}
-				this.file = this.mXmppConnectionService.getFileBackend()
-						.getFile(message, false);
+				this.file = FileBackend.getFile(message, false);
 				if (message.getEncryption() == Message.ENCRYPTION_OTR) {
 					byte[] key = conversation.getSymmetricKey();
 					if (key == null) {
@@ -364,8 +364,7 @@ public class JingleConnection implements Transferable {
 		Content content = new Content(this.contentCreator, this.contentName);
 		if (message.getType() == Message.TYPE_IMAGE || message.getType() == Message.TYPE_FILE) {
 			content.setTransportId(this.transportId);
-			this.file = this.mXmppConnectionService.getFileBackend().getFile(
-					message, false);
+			this.file = FileBackend.getFile(message, false);
 			if (message.getEncryption() == Message.ENCRYPTION_OTR) {
 				Conversation conversation = this.message.getConversation();
 				if (!this.mXmppConnectionService.renewSymmetricKey(conversation)) {
diff --git a/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleInbandTransport.java b/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleInbandTransport.java
index 08b63d5b..94cce09f 100644
--- a/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleInbandTransport.java
+++ b/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleInbandTransport.java
@@ -15,6 +15,7 @@ import de.thedevstack.conversationsplus.entities.Account;
 import de.thedevstack.conversationsplus.entities.DownloadableFile;
 import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.utils.CryptoHelper;
+import de.thedevstack.conversationsplus.utils.StreamUtil;
 import de.thedevstack.conversationsplus.xml.Element;
 import de.thedevstack.conversationsplus.xmpp.OnIqPacketReceived;
 import de.thedevstack.conversationsplus.xmpp.jid.Jid;
@@ -190,7 +191,7 @@ public class JingleInbandTransport extends JingleTransport {
 			}
 		} catch (IOException e) {
 			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": "+e.getMessage());
-			FileBackend.close(fileInputStream);
+			StreamUtil.close(fileInputStream);
 			this.onFileTransmissionStatusChanged.onFileTransferAborted();
 		}
 	}
@@ -214,7 +215,7 @@ public class JingleInbandTransport extends JingleTransport {
 			}
 		} catch (IOException e) {
 			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": "+e.getMessage());
-			FileBackend.close(fileOutputStream);
+			StreamUtil.close(fileOutputStream);
 			this.onFileTransmissionStatusChanged.onFileTransferAborted();
 		}
 	}
diff --git a/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleSocks5Transport.java b/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleSocks5Transport.java
index 2e2ba4fe..72a5d7cb 100644
--- a/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleSocks5Transport.java
+++ b/src/main/java/de/thedevstack/conversationsplus/xmpp/jingle/JingleSocks5Transport.java
@@ -18,6 +18,7 @@ import de.thedevstack.conversationsplus.Config;
 import de.thedevstack.conversationsplus.entities.DownloadableFile;
 import de.thedevstack.conversationsplus.persistance.FileBackend;
 import de.thedevstack.conversationsplus.utils.CryptoHelper;
+import de.thedevstack.conversationsplus.utils.StreamUtil;
 
 public class JingleSocks5Transport extends JingleTransport {
 	private JingleCandidate candidate;
@@ -137,7 +138,7 @@ public class JingleSocks5Transport extends JingleTransport {
 					Log.d(Config.LOGTAG, connection.getAccount().getJid().toBareJid() + ": "+e.getMessage());
 					callback.onFileTransferAborted();
 				} finally {
-					FileBackend.close(fileInputStream);
+					StreamUtil.close(fileInputStream);
 				}
 			}
 		}).start();
@@ -194,7 +195,7 @@ public class JingleSocks5Transport extends JingleTransport {
 					Log.d(Config.LOGTAG, connection.getAccount().getJid().toBareJid() + ": "+e.getMessage());
 					callback.onFileTransferAborted();
 				} finally {
-					FileBackend.close(fileOutputStream);
+					StreamUtil.close(fileOutputStream);
 				}
 			}
 		}).start();