private static function createMissingImage($rtf, $width, $height)
    {
        $stream = fopen('data://text/plain;base64,' . self::getMissingImage(), 'rb');
        $image = new PHPRtfLite_Image_Gd($rtf, $stream, $width, $height);
        $image->setImageType(self::TYPE_PNG);
        $image->setIsMissing();
        return $image;
    }