protected function canCreateTmb($path, $stat) {
		return $this->tmbPathWritable 
			&& strpos($path, $this->tmbPath) === false // do not create thumnbnail for thumnbnail
			&& $this->imgLib 
			&& strpos($stat['mime'], 'image') === 0 
			&& ($this->imgLib == 'gd' ? $stat['mime'] == 'image/jpeg' || $stat['mime'] == 'image/png' || $stat['mime'] == 'image/gif' : true);
	}