public function onPostSerialize(ObjectEvent $event)
    {
        // getSubscribedEvents doesn't seem to support parent classes
        if (!$event->getObject() instanceof MediaInterface) {
            return;
        }

        /** @var MediaInterface $media */
        $media = $event->getObject();

        $provider = $this->getProvider($media);

        if ($provider->getName() == 'image') {
            $images = $this->getImages($media, ['medialibrary']);

            $event->getVisitor()->addData('images', $images);
        }

        $event->getVisitor()->addData('original', $provider->getUrl($media));
    }