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;       
?>   

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