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

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

.thumbnail img:hover
{
    z-index:20;
}

.thumbnail span{ /*CSS for enlarged image*/
position: absolute;
background-color: black;
padding: 3px;
border: 0px dashed gray;
visibility: hidden;
color: black;
text-decoration: none;
color:White;
left:-10000px;
z-index: 0;
}

.thumbnail span img{ /*CSS for enlarged image*/
border-width: 0;
padding: 2px;
z-index: 60;
}

.thumbnail:hover span{ /*CSS for enlarged image on hover*/
visibility: visible;
left:auto;
z-index: 50;
right: 300px; /*position where enlarged image should offset horizontally */
}