public function deleteImageSetBySlug($slug)
    {
        $imageSet = $this->getImageSet();

        foreach ($imageSet as $key => $set) {
            if ($set->slug == $slug) {
                unset($imageSet[$key]);
            }
        }
        $imageSet = array_values($imageSet);
        $this->repository->imageSet = $imageSet;
        $this->save();
    }