PHP 下载远程图片

function GrabImage($url, $filename = '') {
    if ($url == ''):
        return false;
    endif;
    if ($filename == '') {
        $ext = strrchr($url, '.');
        if ($ext != '.gif' && $ext != '.jpg'):
            return false;
        endif;
        $filename = date('His') . $ext;
    }
    ob_start();
    readfile($url);
    $img = ob_get_contents();
    ob_end_clean();
    $size = strlen($img);
    $fp2 = @fopen($filename, 'a');
    fwrite($fp2, $img);
    fclose($fp2);
    return $filename;
}
$img = GrabImage('http://www.ipaye.cn/w/uploads/358897.jpg', '');
if ($img) {
    echo '<pre><img src=' . $img . '></pre>';
} else {
    echo 'false';
}