php 下载网络图片到本地服务器

<?php

$url = "http://res.kumi.cn/templates/kumi/file/2016xiyouji/img/3.png";

//$filename = '1.png';

function GetImage($url, $filename = "") {
if ($url == "") {
return false;
}
if ($filename == "") {
$ext = strrchr ( $url, "." );
if ($ext != ".gif" && $ext != ".jpg" && $ext != ".png") {
return false;
}
$filename = time () . $ext;
}
//文件 保存路径
ob_start ();
readfile ( $url );
$img = ob_get_contents ();
ob_end_clean ();
$size = strlen ( $img );
//文件大小
$fp2 = @fopen ( $filename, "a" );
fwrite ( $fp2, $img );
fclose ( $fp2 );
return $filename;

}

GetImage($url);

GetImage($url,$_SERVER['DOCUMENT_ROOT'].'/5.png');
exit;

?>