PHPePub\Helpers\ImageHelper::isGdInstalled PHP Method

    public static function isGdInstalled()
    {
        if (!isset(self::$isGdInstalled)) {
            self::$isGdInstalled = (extension_loaded('gd') || extension_loaded('gd2')) && function_exists('gd_info');
        }
        return self::$isGdInstalled;
    }