kiev, did that chubby oldman appear in the game? Otherwise, I believe the image is possibly an edited CG. It is really rare to re-use old sprites in newer games.
My reasons:
1. The menu and the girl's sprite is highly possible from 淫妖蟲 悦~快楽変化退魔録 and then edited.
2. The timespan from the original game came out till the image was posted. There's more than enough time to extract, edit and posting 1 image, there's enough time for it to be a modded game.
3. Zooming in closer, some pixels has some mismatched coloring compared to their surrounding, making it more viable to be edited sprite.
(4). That old guy didn't appear in the game originally. (need confirmation)
Still it's just circumstancial "evidents", and not definitive. But personally I'm tilting to either edited CG or a fangame/modded game.