def primary_image(self):
        """
        Returns the primary image for a product. Usually used when one can
        only display one product image, e.g. in a list of products.
        """
        images = self.get_all_images()
        ordering = self.images.model.Meta.ordering
        if not ordering or ordering[0] != "display_order":
            # Only apply order_by() if a custom model doesn't use default
            # ordering. Applying order_by() busts the prefetch cache of
            # the ProductManager
            images = images.order_by("display_order")
        try:
            return images[0]
        except IndexError:
            # We return a dict with fields that mirror the key properties of
            # the ProductImage class so this missing image can be used
            # interchangeably in templates.  Strategy pattern ftw!
            missing_image = self.get_missing_image()
            return {"original": missing_image.name, "caption": "", "is_missing": True}

ordering = self.images.model.Meta.ordering

class ProductImage(auto_prefetch.Model, AbstractProductImage):
	product = auto_prefetch.ForeignKey(
		"catalogue.Product",
		on_delete=models.CASCADE,
		related_name="images",
		verbose_name=_("Product"),
	)

	class Meta(auto_prefetch.Model.Meta, AbstractProductImage.Meta):
		pass