html{height: 100%;}

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

.thumbnail img{
border: 1px solid white;
margin: 5px 0px 5px 0px;
}

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

.thumbnail:hover img{
border: 5;
}

.thumbnail span{ /*CSS for enlarged image*/
position: absolute;
background-color: 0;
padding: 0px;
left: -1000px;
border: 0px dashed gray;
visibility: hidden;
color: none;
text-decoration: none;
}

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

.thumbnail:hover span{ /*CSS for enlarged image*/
visibility: visible;
top: 0;
left: 168px; /*position where enlarged image should offset horizontally */
z-index: 50;
}