php下载图片方法

<?php

function getImage($url,$filename="") {

if($url=="") return false;

if($filename=="") {
$ext=strrchr($url,".");
if($ext!=".mp3") return false;
$filename=date("YmdHis").$ext;
}

ob_start();
readfile($url);
$img = ob_get_contents();
ob_end_clean();
$size = strlen($img);
$filename=mb_convert_encoding($filename, "gbk", "UTF-8");
$fp2=@fopen($filename, "w");
fwrite($fp2,$img);
fclose($fp2);
echo $filename;
return $filename;
}

//getImage('http://kasadi-pic.stor.sinaapp.com/1,369,708,463.jpg',__DIR__.'/downpic2/111.jpg');
//echo '下载完成';

?>