.thumbnail{
            position: relative;
            z-index: 0;
            }

.thumbnail:hover{
                  background-color: transparent;
                  z-index: 50;
                  }

.thumbnail span{ /*CSS for enlarged image*/
                 position: absolute;
                 background-color: lightyellow;
                 padding: 10px;
                 left: -1000px;
                 border: 1px dashed gray;
                 visibility: hidden;
                 color: black;
                 text-decoration: none;
                 }

.thumbnail span img{ /*CSS for enlarged image*/
                     border-width: 0;
                     padding: 2px;
                     }

.thumbnail:hover span{ /*CSS for enlarged image on hover*/
                       visibility: visible;
                       top: 30px;
                       left: 0px; /*position where enlarged image should offset horizontally */

                       }