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

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

.thumbnail span{ 
position: absolute; 
background-color: lightyellow; 
padding: 5px; 
left: -2000px; 
border: 1px dashed gray; 
visibility: hidden; 
color: black; 
text-decoration: none; 
} 

.thumbnail span img{ 
border-width: 0; 
padding: 2px; 
} 

.thumbnail:hover span{ 
visibility: visible; 
top: 0; 
left: -180px; 

}