So for example a future image compression algorithm should define how to compress a single image, and how to compress a group of compressed images? Interesting

So for example a future image compression algorithm should define how to compress a single image, and how to compress a group of compressed images? Interesting thought. The downside of this coupling might be slower adoption of new cross-file compression algorithms if there is going to be a string of them, which empirically there seems to be. It's kind of funny that the de facto image compression algorithms haven't changed in ~10 years whereas video compression algorithms change flavors every two to four years.