Massive +1. I always found myself how neat it would be to have different image vers without it being counted towards the final image count, esp. when artists I commission give me different versions. Would also be useful for stuff like non-nsfw/l vers, references with/without shading... kinda makes me excited thinking about it not gonna lie.
For example when you get a piece of art with a background version and a transparent version, or shaded and unshaded, and youd like to upload both but dont really want to have 2 pieces of technically the same art in your gallery? maybe an option for an image to have 2 modes that could be clicked between or something?
+1 this would be super useful for art crediting too... rn I have three separate versions of one art piece credited to me and it bothers me a lot lol