public function getGravatar($email, $size = null, $rating = null, $default = null, $secure = null)
    {
        $hash = $this->getHash($email);

        $map = array(
            's' => $size ?: $this->settings['size'],
            'r' => $rating ?: $this->settings['rating'],
            'd' => $default ?: $this->settings['default'],
        );

        if (null === $secure) {
            $secure = $this->settings['secure'];
        }

        return ($secure ? 'https://secure' : 'http://www').'.gravatar.com/avatar/'.$hash.'?'.http_build_query(array_filter($map));
    }