WRT the discussion here (mav, Jimbo) about the validity or otherwise of the British Portrait Gallery's enquiry, I have posted on wikipedia-l about the British (and Australian) legal situation; have a look at the recent archives for the details. To cut a long story short galleries in Australia, and now it seems Britain, think they have the legal right to impose these restrictions under their own copyright laws, and from my reading of the literal text they may be right (though there may be precedents in the area that say otherwise, IANAL).
We may be in the situation where it might be illegal for a British or Australian user to take an image from a gallery website of a PD artwork, and put it on the Wikipedia, but not for an American user to do so. Then again, maybe they'd like to try to extradite the American user in that situation...in other words, it's potentially a legal mess and I'm not liking their chances of successfully pursuing us. I suspect this could keep Larry Lessig and Eben Moglan amused for weeks.
If I were Jimbo, I'd be tempted to deliberately perpetuate an American stereotype and tell the National Portrait Gallery to kiss our ass and sue if they dare...but I'd perhaps want to get a real legal opinion first.