Sulu\Bundle\MediaBundle\Controller\MediaPreviewController::deleteAction PHP Method

    public function deleteAction($id, Request $request)
    {
        try {
            $mediaManager = $this->getMediaManager();
            $locale = $this->getLocale($request);
            $media = $mediaManager->getById($id, $locale);
            /** @var MediaInterface $mediaEntity */
            $mediaEntity = $media->getEntity();
            if ($mediaEntity->getPreviewImage() !== null) {
                $oldPreviewImageId = $mediaEntity->getPreviewImage()->getId();
                $mediaEntity->setPreviewImage(null);
                $mediaManager->delete($oldPreviewImageId);
            }
            $view = $this->view(null, 204);
        } catch (MediaNotFoundException $e) {
            $view = $this->view($e->toArray(), 404);
        } catch (MediaException $e) {
            $view = $this->view($e->toArray(), 400);
        }
        return $this->handleView($view);
    }