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

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

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

.thumbnail:hover img{
border: 1px solid grey;
}

.thumbnail span{ /*CSS for enlarged image*/
position: absolute;
background-color: lightyellow;
padding: 5px;
left: -350px;
height: 300px
width: 300px
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*/
visibility: visible;
top: 0;
bottom: 0;
left: 150px; /*position where enlarged image should offset horizontally */
z-index: 50;
}

.ul {
position:relative;
width:540px;
margin:auto;
background:url(cheerslogo500.jpg) 125px 70px no-repeat;
border:1px solid #ccc; 
height:525px;
padding-left:5px;
}