Django: Overriding save method for specific model scenarios

In situations where the save method of a Django model needs to be modified based on certain criteria, such as determining if an image was updated or only the description changed, a custom approach can be employed.

One technique involves using a property and a flag:

class Model(model.Model):
    _image = models.ImageField(upload_to='folder')
    thumb = models.ImageField(upload_to='folder')
    description = models.CharField()

    def set_image(self, val):
        self._image = val
        self._image_changed = True

    def get_image(self):
        return self._image

    image = property(get_image, set_image)

    def save(self, *args, **kwargs):
        if getattr(self, '_image_changed', True):
            # Logic for image rescaling
        super(Model, self).save(*args, **kwargs)

This approach ensures that the image rescaling logic is only triggered when the '_image_changed' flag is set to True, indicating that the image has been modified.