piwigo/themes/default/fix-ie7.css

/* fix IE with another layout for thumbnails */

.content UL.thumbnails SPAN.wrap2 {
  display: block;
  position: relative;
  text-align: left;
}
.content UL.thumbnails SPAN.wrap2 A,
.content UL.thumbnails SPAN.wrap2 SPAN {
  overflow: visible;
  position: absolute;
  top: 50%;
  text-align: center;
}

.content UL.thumbnails IMG.thumbnail {
  position: relative;
  top: -50%;   
  margin-top: 2%;
}