/*本物の画像用*/ 
div.gazou1{ 
width:250px; 
height:200px; 
top:200px; 
left:500px; 
position:absolute; 
z-index:1; 
visibility:visible; 
} 
/*ダミーの画像用*/ 
div.gazou2 { 
width:250px; 
height:200px; 
top:200px; 
left:500px; 
position:absolute; 
z-index:2; 
visibility:visible; 
}