source: extensions/GThumb/template/gthumb.css

#thumbnails {
  overflow: hidden;
}

#thumbnails .gthumb {
  position: relative;
  overflow: hidden;
  float: left;
  display: inline;
  background: none !important;
}

#thumbnails .gthumb a {
  position: absolute;
  z-index:0;
}

#thumbnails .gthumb a img.thumbnail,
#thumbnails .gthumb a img.thumbnail:hover {
  border: 0 none;
  margin: 0;
  padding: 0;
  top: 0;
}

#thumbnails .gthumb .thumbLegend {
  position:absolute;
  z-index:100;
  bottom:-40px;
  top:auto;
  height:30px;
  left:0;
  right:0;
  padding:5px 0;
  width:100%;
  background:rgba(0,0,0,0.7);
  text-align:center;
  overflow:hidden;
  color:#aaa;
  -webkit-transition:all 200ms ease-out;
  -moz-transition:all 200ms ease-out;
  -ms-transition:all 200ms ease-out;
  -o-transition:all 200ms ease-out;
  transition:all 200ms ease-out;
}
  #thumbnails .gthumb:hover .thumbLegend {
    bottom:0px;
  }
#thumbnails .thumbLegend .thumbName {
  display:block;
  font-weight:bold;
  color:#eee;
}