Symfony2通过响应发送用imagecreate（）创建的图像（httpfoundation）

I want to send simple image through httpgoundation response, from one controller to another. Here's my code:

    $string = (string)md5(uniqid());
    $string = substr($string, 0, $length);

    $image = imagecreate(200, 50);
    imagefill($image, 0, 0, "#000000");

    $headers= array(
        'Content-type'=>'image/jpeg',
        'Pragma'=>'no-cache',
        'Cache-Control'=>'no-cache'
    );

    $response = new Response( $image, 200, $headers );

    return new Response($response);

The error says The Response content must be a string or object implementing __toString(). Seeking the answer using google I only found people who want to return file somewhere from server(an asset). What should I do to get this working?

You have to use return $response; instead of return new Response($response);

And you have to convert image resource to string. Do the following:

    $string = (string)md5(uniqid());
    $string = substr($string, 0, $length);

    $image = imagecreate(200, 50);
    imagefill($image, 0, 0, "#000000");

    $headers= array(
        'Content-type'=>'image/jpeg',
        'Pragma'=>'no-cache',
        'Cache-Control'=>'no-cache'
    );

    ob_start();
    imagejpeg($img);
    $imageString = ob_get_clean();

    return new Response( $imageString, 200, $headers );