Just in case you haven't realised, ChatGPT's responses are influenced by the filename you hand it. If you're sticking with the default filename it gives you, you're passing hints to the next generation via a backchannel.
Good point -- in this case I'm using the URL it passes back, which was the only information it had. The original one was passed either as base64 encoded or a URL. IIRC the URL they passed back was random-feeling, but I'd have to look to check it out. Its possible that the initial URL encoded a little more, depending on how the filename works, but my guess is that the model is good enough that, say, "royce_hall.jpeg" wouldn't change it too drastically, especially not over time...