[ekianjo]

Does the Museum actually own the work of art? I think they probably own the physical object but isnt its artistic expression considered as intellectual property and therefore wouldnt it fall in the public domain?

As for the lost revenue claim, then what about the pictures of paintings you find everywhere? Wouldnt they cause lost revenue as well if we follow that logic?

[sp332]

It's not copyrighted, so the intellectual property is in the public domain. But this doesn't mean they are prohibited from hiding the object, or making people contractually agree not to take photos.

In the USA, there are certain fair use rights that let you copy a work without a license. It's a big gray area, usually it's OK if it's for purposes of commentary or education, and not for commercial use. Other jurisdictions are probably more strict.