yii\imagine\BaseImage::createImagine PHP Method

    protected static function createImagine()
    {
        foreach ((array) static::$driver as $driver) {
            switch ($driver) {
                case self::DRIVER_GMAGICK:
                    if (class_exists('Gmagick', false)) {
                        return new \Imagine\Gmagick\Imagine();
                    }
                    break;
                case self::DRIVER_IMAGICK:
                    if (class_exists('Imagick', false)) {
                        return new \Imagine\Imagick\Imagine();
                    }
                    break;
                case self::DRIVER_GD2:
                    if (function_exists('gd_info')) {
                        return new \Imagine\Gd\Imagine();
                    }
                    break;
                default:
                    throw new InvalidConfigException("Unknown driver: {$driver}");
            }
        }
        throw new InvalidConfigException('Your system does not support any of these drivers: ' . implode(',', (array) static::$driver));
    }