PHP中用header图片地址 简单隐藏图片源地址

<?php        
$path=$_GET["path"];        
$cacheimgname=str_replace("/","_",$path);        
$localimg="upimg/".$cacheimgname;        
if ((file_exists($localimg)))        
{        
$httpurl=$localimg;        
}        
else       
{        
$httpurl="http://www.imageserver.com/".$path;        
@copy($httpurl,$localimg);//缓存图片！        
}        
header("Locationhttpurl");        
exit;        
?>   

调用它类似这样：

<img src="img.php?path=x/x/xtest.gif">