Quick query:
In the case with many image processing stacks, for related, similar, og:image, ld+json, shortcode, etc, if the same image resource is processed twice with the same options, from the same location, is it uniquely renamed and stored in the same location?
Of course it would be far fetched for Hugo to keep track of double processing, but it makes sense to check here, if setting scratch variables and checking for them in every image processing stack is avoidable.