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; 
    }