PHP下載遠程文件到本地存儲的代碼

<?php
function GrabImage($url,$filename="") {
    if($url=="") return false;
    if($filename=="") {
        $ext=strrchr($url,".");
        if($ext!=".gif" && $ext!=".jpg") return false;
        $filename=date("dMYHis").$ext;
    }
    ob_start();
    readfile($url);
    $img = ob_get_contents();
    ob_end_clean();
    $size = strlen($img);
    $fp2=@fopen($filename, "a");
    fwrite($fp2,$img);
    fclose($fp2);
    return $filename;
}
function gethttpimage($url){ 
    if(!empty($url)){ 
        $filename=uniqid().strrchr($url,"."); 
        echo $filename;
        $get_file=@file_get_contents($url);  
        if($get_file){ 
            $fp=@fopen($filename,"w"); 
            @fwrite($fp,$get_file); 
            @fclose($fp); 
        }  
        return $imgUrl; 
    }else{ 
        return false; 
    }  
} 
//$img=GrabImage("http://s15.sinaimg.cn/middle/46f37fb5g93953685ea0e&690.jpg","");
$img=gethttpimage("http://s15.sinaimg.cn/middle/46f37fb5g93953685ea0e&690.jpg","");
if($img) echo '<pre><img src="'.$img.'"></pre>';
else echo "false";
?>