IMO, it is very difficult to prove 1: If that watermark is recognizable enough to be a getty watermark or something whose shape vaguely looks like a watermark.

IMO, it is very difficult to prove 1: If that watermark is recognizable enough to be a getty watermark or something whose shape vaguely looks like a watermark. 2. Where that watermark is coming from. From how the model is trained, it is possible that the model considers the watermark itself a style of the picture and mimics it. But it would be mission impossible to trace to a particular work that the inspiration is coming from.