public function preview($id = null)
    {
        $photo = $this->Photos->findPendingById($id)
            ->select(['id', 'album_id', 'filename'])
            ->contain([$this->Photos->Albums->getAlias() => ['fields' => ['id', 'title', 'slug']]])
            ->firstOrFail();

        $this->set(compact('photo'));
        $this->render('view');
    }