code: def _replace_old_image(self):
          ''' Override this in subclass if you don't want
              image replacing or want to customize image replacing
          '''
          try:
              old_obj = self.__class__.objects.get(pk=self.pk)
              if old_obj.image.path != self.image.path:
                  path = old_obj.image.path
                  default_storage.delete(path)
          except self.__class__.DoesNotExist:
              pasf _replace_old_image(self):
          ''' Override this in subclass if you don't want
              image replacing or want to customize image replacing
          '''
          try:
              old_obj = self.__class__.objects.get(pk=self.pk)
              if old_obj.image.path != self.image.path:
                  path = old_obj.image.path
                  default_storage.delete(path)
          except self.__class__.DoesNotExist:
              pass
docs: Override this in subclass if you don't want
              image replacing or want to customize image replacing