public function createImage($width, $height, $format)
    {
        $image = new \Imagick();
        $pixel = new \ImagickPixel('none');
        $image->newImage(intval($width), intval($height), $pixel);
        $image->setImageFormat($format);
        $this->colorNumber = $image->getImageColors();
        $this->pixelNumber = 0;
        $content = $image->getimageblob();
        $image->destroy();
        unset($image);
        return $content;
    }