代码：
test.php
<img src="test3.php?path=file/118812060.jpg">
<br>this is test!
test3.php
<?php
$path=$_GET["path"];
$cacheimgname=str_replace("/","_",$path);
$localimg="testimg/".$cacheimgname;
if ((file_exists($localimg)))
{
$httpurl=$localimg;
}
else
{
$httpurl="http://www.domain.com/".$path;
@copy($httpurl,$localimg);//缓存图片！
}
header("Location:$httpurl");
exit;
?>实际地址为：testimg/file_118812060.jpg
