php 图片批量下载

<?php    $url = "http://photo.hupu.com/nba";  $content=file_get_contents($url);  $reg="/<img.*?src=\"(.*?)\".*?>/";    preg_match_all($reg,$content,$matches);    $path = './imgDownload';  if(!file_exists($path)){      mkdir($path, 0777);  }    for($i = 0;$i < count($matches[1]);$i ++){            /*explode     $url_arr[$i] = explode('/', $matches[1][$i]);     $last = count($url_arr[$i])-1;     */            //strrchr         $filename = strrchr($matches[1][$i], '/');            downImage($matches[1][$i],$path.$filename);      //downImage($matches[1][$i],$path.'/'.$url_arr[$i][$last]);  }    function downImage($url,$filename="") {      if($url=="") return false;        if($filename=="") {          $ext=strrchr($url,".");          if($ext!=".gif" && $ext!=".jpg" && $ext!=".png" && $ext!="jpeg") return false;          $filename=date("YmdHis").$ext;      }        ob_start();      //make file that output from url goes to buffer      readfile($url);      //file_get_contents($url);  这个方法不行的！！！只能用readfile      $img = ob_get_contents();      ob_end_clean();        $fp=@fopen($filename, "a");//append      @fwrite($fp,$img);            @fclose($fp);        return $filename;  }