.thumbnail-item { 
   position: relative; 
   float: left;  
   width: 159px;
   height: 179px;
}
.thumbnail-item a { 
   display: block; 
}
.tooltip { 
   display: none; 
   position: absolute; 
}
.tooltip span.overlay { 
   border:1px solid #ccc;
   position: absolute; 
   top: 0px; 
   left: 0px; 
   display: block; 
   width: 350px; 
   height: 200px;
}