Nothing from the OP or the original AI Artist was about using Adobe.

That said, were the images used by Adobe actually licensed for AI training, or was an existing overly broad license aimed at "showing this in an online gallery" interpreted by lawyers to include AI training? Because that latter option is being done by a lot of corporations (including Google) to make "ethical" AI models.

If any if the training set is public domain or creative commons, I'd argue that this make the image at best an integration work, not derivative nor fair use, and as bits from the images are indistinguishable from each other, you shouldn't be able to license it.

Like code generated from models trained on AGPL/GPLv3 licensed code should also be AGPL/GPLv3.