bug 937 fixed: makes sure a user won't see the thumbnail of a photo that has a

higher privacy level than user privacy level.

For an acceptable solution at performance level, I have implemented a cache:
for a given user, each album has a representative_picture_id. This cache also
avoids to perform numerous "order by rand()" SQL queries which is the case
when $conf['allow_random_representative'] = true;


git-svn-id: http://piwigo.org/svn/trunk@8802 68402e56-0260-453c-a942-63ccdbb3a9ee

install/piwigo_structure-mysql.sql

@@ -368,6 +368,7 @@ CREATE TABLE `piwigo_user_cache_categories` (
   `nb_images` mediumint(8) unsigned NOT NULL default '0',
   `count_images` mediumint(8) unsigned default '0',
   `count_categories` mediumint(8) unsigned default '0',
+  `user_representative_picture_id` mediumint(8) unsigned default NULL,
   PRIMARY KEY  (`user_id`,`cat_id`)
 ) TYPE=MyISAM;