private function compileFastlyParameters()
    {
        if (isset($this->fastlyParameters['width']) == false) {
            $this->fastlyParameters['height'] = $this->_height;
            $this->fastlyParameters['width'] = $this->_width;
        }

        $params = [];
        foreach ($this->fastlyParameters as $key => $value) {
            $params[] = $key . '=' . $value;
        }

        return implode('&', $params);
    }