php图片下载

function iDownload(){

$name=$_GET['name']; //获取图片地址$file = fopen($dir,"r"); // 打开文件
$dir='/www/image/';$ext=strrchr($name,".");

if($ext!=".gif" && $ext!=".jpg" && $ext!=".png")
return false;

$file_path=$dir.$name;
$size=filesize($file_path);
$file = fopen($file_path,"r") or die("file is not exist");; // 打开文件

Header("Content-type: application/octet-stream");
Header("Accept-Ranges: bytes");
Header("Accept-Length: ".$size);
Header("Content-Disposition: attachment; filename=" . $name);
echo fread($file,$size);
fclose($file);
exit;
}