Login.php，getCaptcha($path)函数中，为何是判断statusCode=200的时候报错呢？

[Kabutack]

public function getCaptcha($path)
{
    $url = Config::get('url.login_captcha');
    $cookie = new CookieJar();
    $codePath = $path . sha1($this->getUsername() . '-' . microtime(true)) . '.gif';
    $options = ['cookies' => $cookie, 'save_to' => $codePath];
    $response = $this->request('get', [$url, [], $options]);
    // Check the StatusCode 
    if ($response->getStatusCode() == 200) {
        throw new HttpException('get the captcha failed!', 10005);
    }
    return $codePath;
}