public function getDefaultPngCompressionLevel()
    {
        $result = $this->config->get('concrete.misc.default_png_image_compression');
        if ($this->valn->integer($result, 0, 9)) {
            $result = (int) $result;
        } else {
            $result = static::DEFAULT_PNG_COMPRESSIONLEVEL;
        }

        return $result;
    }