Any photo could be AI at this point. Either you close the contest for good or you accept all contestants. Disqualifying on a hunch dismisses all semblance of credibility. I mean of course it looks off, that’s the point of the photo you silly judge.
Only tangentially related, but… I can’t help but think this sort of constant paranoia is bad news. Step 1 of getting someone in a cult or into conspiracy theories is to suspend belief in commonly accepted information.