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

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

.thumbnail span{ 
position: fixed;
background-color: white;
width: 300px;
height: 240px;
padding: 5px;
left:50px;top:50px;
border: 2px solid blue;
visibility: hidden;
color: #FFFF00;
text-decoration: none;
}

.thumbnail span img{ 
border-width: 0;
width:300px;
height:240px;
padding: 2px;
}

.thumbnail:hover span{
visibility: visible;
left:400px;top:200px;
}