http://www.w3school.com.cn/cssref/pr_text-shadow.asp
http://www.w3school.com.cn/cssref/pr_box-shadow.asp
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html charset=gb2312" />
<title>Untitled Document</title>
<style type="text/css">
div#pic{
background: url(http://cache.soso.com/wenwen/i/nlogo_ask1.gif) left top
width: 151px
height: 47px
border: 1px solid #000000
}
div#shadow{
width: 151px
height: 47px
background: #CCCCCC /*阴影颜色*/
position: relative /*设置阴影图层的位置为相对定位*/
left: 5px
top: -44px
z-index: -1 /*把阴影图层置于最底层*/
}
</style>
</head>
<body>
<div id="pic"></div>
<div id="shadow"></div>
</body>
</html>