class PhotoManager(models.Manager):
    # Only returns one object, not a list of them
    def latest(self):
        end = datetime.now()
        start = end - timedelta(hours=24)
        return super(PhotoManager, self).get_queryset().filter(
            Q(timestamp__gte=start) & Q(timestamp__lte=end))

    def most_liked(self):
        return super(PhotoManager, self).get_queryset().annotate(
            the_count=(Count('likers'))).order_by('-the_count’)

class Photo(models.Model):
    likers = models.ManyToManyField(settings.AUTH_USER_MODEL,
                                    related_name='likers', blank=True)
    photo = models.ImageField(upload_to=upload_location)
    timestamp = models.DateTimeField(auto_now_add=True)

    objects = PhotoManager()

def view(request):
    most_liked = Photo.objects.most_liked()[:300]