public static function with_ftp($config = 'default', $connect = true)
	{
		if (static::$with_ftp = \Ftp::forge($config, $connect))
		{
			// if we have an ftp object, activate the move callback
			static::$upload->setConfig('moveCallback', '\\Upload\\move_callback');
		}
		else
		{
			// creating the ftp object failed, disable the callback
			static::$upload->setConfig('moveCallback', null);
		}
	}