So I contacted the reseller and they said yes, Games Workshop insists they remove all images of Games Workshop products. They admitted it probably wasn't legal, but it wasn't worth the legal fight.
I have to admit I find the whole thing bizarre. It would be like Ford, GM or Toyota saying used car dealers can't use pictures of their cars in their ads.
Games Workshop has a reputation among brick retailers as well, and frankly I don't think the hobby needs this sort of attitude. They're games, not life-saving medicines. There's plenty of fish in this sea and there's no profit in being the stinky ones.