.gallerycontainer{
position: relative;
/*Add a height attribute and set to largest image's height to prevent overlaying*/
}

.thumbnail img{
display: inline;
padding-right:.33em;
}

.thumbnail:hover{
background-color: transparent;
}

/*.thumbnail:hover img{

}*/

.thumbnail span{ /*CSS for enlarged image*/
position: absolute;
padding: 0px;
visibility: hidden;
}

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

}

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

}