def preview(request, image_id, filter_spec):
    image = get_object_or_404(get_image_model(), id=image_id)

    try:
        response = HttpResponse()
        image = Filter(spec=filter_spec).run(image, response)
        response['Content-Type'] = 'image/' + image.format_name
        return response
    except InvalidFilterSpecError:
        return HttpResponse("Invalid filter spec: " + filter_spec, content_type='text/plain', status=400)
dataset/ETHPy150Open torchbox/wagtail/wagtail/wagtailimages/views/images.py/preview/original