ColorThief\Image\Adapter\GDImageAdapter::loadFile PHP Метод

    public function loadFile($file)
    {
        list(, , $type) = @getImageSize($file);
        switch ($type) {
            case IMAGETYPE_GIF:
                $this->resource = imagecreatefromgif($file);
                break;
            case IMAGETYPE_JPEG:
                $this->resource = imagecreatefromjpeg($file);
                break;
            case IMAGETYPE_PNG:
                $this->resource = imagecreatefrompng($file);
                break;
            default:
                throw new \RuntimeException("Image '" . $file . "' is not readable or does not exists.");
                break;
        }
    }