What is the worst that could happen if someone objected to those fine images being displayed on a small website like mine — one that is, in the strictest sense, making a "non-commercial use" of them?
In theory, the worst case is that you get targeted by a copyright troll. The U.S. civil courts make it far too easy to wage "lawfare" against innocent people, and make a profit at it because the targets are given to understand that it's cheaper to pay than to fight.
https://www.online-paralegal-degree.org/copyright-trolls/
https://en.wikipedia.org/wiki/Copyright_troll