#div1 { width: 200px; height: 200px; padding: 5px; border: 1px solid #ccc; position: relative; }

#div1 .small_pic { width: 200px; height: 200px; background: #eee; position: relative; }
#div1 .float_layer { width: 50px; height: 50px; border: 1px solid #000; background: #fff; filter: alpha(opacity: 30); opacity: 0.3; position: absolute; top: 0; left: 0; display:none; }
#div1 .mark {width:100%; height:100%; position:absolute; z-index:2; left:0px; top:0px; background:red; filter:alpha(opacity:0); opacity:0;}
#div1 .big_pic { position: absolute; top: -1px; left: 215px; width:250px; height:250px; overflow:hidden; border:2px solid #CCC; display:none; }
#div1 .big_pic img { position:absolute; top: -30px; left: -80px; }