example.py

class TrackMessageView(APIView):
    renderer_classes = [JPEGRenderer]

    @property
    def pixel(self):
        return open(os.path.join(settings.STATIC_ROOT, 'site/img/pixel.jpg'), 'rb')

    def get(self, request, *args, **kwargs):
        manager = BaseManager()
        message = manager.get_message_by_unique_id(self.kwargs['unique_id'])
        if message:
            manager.track_message(message)
            return Response(self.pixel.read(), status=201)
        return Response(status=404)