Gemini often rejects photos of random people (even ones it generated itself) because it thinks they look too similar to some well known person.

I don't know tbh. I've tried it on 10-20 various level of famous standups and Gemini refuses every time

Just for testing, I just tried this https://i.ytimg.com/vi/_KJdP4FLGTo/sddefault.jpg ("Redesign this image in a brutalist graphic design style"). Gemini refuses (api as well as UI), OpenAI does it