That's a good example. With a local install of Stable Diffusion 1.5 (which is the base AI that most of these sites use), there is a green-screen plugin (aka a "Lora")  for it. Using that and Photoshop (the new AI Photoshop, or old Photoshop + the Primatte Chromakey plugin) you could easily make a cut-out of the figure shown the AI enhanced render, then paste the cut-out back over the Poser render. That would keep the background consistent at least. Maybe also then blur the background a little, to give a sense of depth. 

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