AI research is old. There's an (apocryphal?) 30 year old tale about using computer vision to detect tanks.

All the photos of tanks had clouds in the sky. And few to none of the counter examples had clouds. So darpa paid for an expensive cloud detector.

Without more information about the study, I'm guessing there's a 'M' or 'F' stamped on the image somewhere.

_edit_ Ah - https://gwern.net/tank the tank story