php curl下载图片 URL地址

<?php
    $url = 'http://mf1905.com/upload/video_img/df3074c98ec5124ad47c52ff59f74e04_middle.jpeg';   

    function http_get_data($url) {   

        $ch = curl_init ();
        curl_setopt ( $ch, CURLOPT_CUSTOMREQUEST, 'GET' );
        curl_setopt ( $ch, CURLOPT_SSL_VERIFYPEER, false );
        curl_setopt ( $ch, CURLOPT_URL, $url );
        ob_start ();
        curl_exec ( $ch );
        $return_content = ob_get_contents ();
        ob_end_clean ();   

        $return_code = curl_getinfo ( $ch, CURLINFO_HTTP_CODE );
        return $return_content;
    }   

    $return_content = http_get_data($url);
    $filename = 'test.jpg';
    $fp= @fopen($filename,"a"); //将文件绑定到流 
    fwrite($fp,$return_content); //写入文件