class Image(models.Model):
    product = models.ForeignKey(Product, related_name='images', on_delete=models.CASCADE)
    # we need this key to the original image because otherwise we can get/update individual cropped images
    parent = models.ForeignKey('self', blank=True, null=True, verbose_name='original image', on_delete=models.CASCADE)
    image = models.ImageField(upload_to=file_upload_to)
    image_type = models.CharField(max_length=50)

if crop_image(disk_path, new_disk_path, size):
        Image.objects.update_or_create(image_type=type_key, parent_id=parent_id, product_id=product_id,
                                              defaults={'image': new_db_path})