public function stroke($BrowserExpire = false)
    {
        if ($this->TransparentBackground) {
            imagealphablending($this->Picture, false);
            imagesavealpha($this->Picture, true);
        }

        if ($BrowserExpire) {
            header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
            header("Cache-Control: no-cache");
            header("Pragma: no-cache");
        }

        header('Content-type: image/png');
        imagepng($this->Picture);
    }