The photograph issue is a hard one--we have had similar problems.
Your friend is right in saying that the photograher will own the
copyright to the images. This, of course, can all be taken care
of with a carefully devised contract where the photographer sells
the copyright to the museum. In some cases, this is a difficult
thing to negotiate--but not impossible. Your first stop should be
legal council.
Good luck.
John Handley