App or community for "Is this AI?"

Anything we can provide is just a drop in the ocean of data they already have. Plus, this was how image generation worked before we got diffusion models (see "generative adversarial networks") and they never reached the level of image quality that diffusion models did.

I don’t think a community for it is an unreasonable idea - at least for now, many AI images are easily identifiable by defects / lack of reasoning in the image. Though there isn’t a good computer program that can do this, I agree.