public function getProfileHeader(bool $mobile = false) : ? string
    {
        //$this->cdn
        $cdn = \Phalcon\DI::getDefault()->getCdn() . '/profile_headers/';
        $header = null;
        $image = !$mobile ? $this->profile_header : $this->profile_header_mobile;

        if (!empty($this->profile_header)) {
            $header = $cdn . $image;
        }

        return $header;
    }