如何修改样式 ul li img

ie6下有问题li之间有点缝隙
但是ie8 ff chrome下是对的
该如何修改了
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title></title>
<style type="text/css">#container3{
height:210px; width:400px;position:relative; overflow:hidden; margin:16px;*margin:16px 0px 0px 9px;float:left; z-index:10; border:1px solid #666666;
}
 #container3 ul{
 height:840px; width:400px; position:absolute;padding:0px; margin:0px; background-color:#FFFF00
}
#container3 ul li{
list-style:none;height:210px; width:400px;padding:0px; margin:0px; 
}
#container3 ul li img{
height:210px; width:400px;
}</style>
</head><body>
<div id="container3">
<ul id="block3">
<li><img src="http://img1.gtimg.com/news/pics/25076/25076064.jpg"/></li>
<li><img src="http://img1.gtimg.com/news/pics/25076/25076064.jpg"/></li>
<li><img src="http://img1.gtimg.com/news/pics/25076/25076064.jpg"/></li>
<li><img src="http://img1.gtimg.com/news/pics/25076/25076064.jpg"/></li>
</ul>
</div><script type="text/javascript">
window.onload = function(){
var i=0;
setInterval(function(){--i;document.getElementById('block3').style.top=i+'px'},100)
}
</script>
</body>
</html>