public function gravatar()
    {
        // Check for valid gravatar
        $gravCheck = 'http://www.gravatar.com/avatar/'. md5( strtolower( trim( $this->email ) ) ) .'.png?d=404';
        $response  = get_headers($gravCheck);

        // If a valid gravatar URL is found, use the gravatar image
        if ($response[0] != "HTTP/1.0 404 Not Found"){
            return 'http://www.gravatar.com/avatar/'. md5( strtolower( trim( $this->email ) ) ) .'.png?s=200&d=blank';
        }

        // If no other image is set, use the default
        return '/img/no_user.png';
    }