'Force DRF\'s content negociation to not raise an error - It wants to use
the format passed to the URL, but we don\'t care since we only deal with
"raw" content: we don\'t even use the renderers.'

def perform_content_negotiation(self, request, force=False):

    return super(CollectionImageViewSet, self).perform_content_negotiation(request, force=True)
