body {
	background:#FFF;
	margin:50px; 
	padding:0; 
	width:800px; 
	height:100%; 
	overflow:hidden; 
	}
	
#background{
	   width:800px;
       height:100%;
	   position: absolute;
	   top:50%;
	   left:50%;
	   margin-left:-400px;
	   margin-top:-300px;
	   z-index:100;
}
/*#bg {
  position: fixed; 
  top: 50%; 
  left: 0%; 
  width: 200%; 
  height: 200%;
}
#bg img {
  position: absolute; 
  top: 50%; 
  left: 0; 
  right: 0; 
  bottom: 0; 
  margin: auto; 
  min-width: 50%;
  min-height: 50%;
}
*/