So, I ask that
in the same way as we have a well defined and well publicised
system for using fair-use on en:WP but not on commons (or de:WP for example)
we should also make a well defined, consistent and well publicised system
for dealing with self-made photographs of in-copyright artwork.
It doesn't happen very often. In addition it is getting into the area
of derivative works which is messy and Freedom of panorama which is
lengthy. The relevant commons pages are at:
http://commons.wikimedia.org/wiki/COM:DW
http://commons.wikimedia.org/wiki/COM:FOP
Self-made pictures of in-copyright artwork is derivative work and cannot be
published or licensed at all without the consent of the original copyright
holder. Notable exceptions include "Freedom of Panorama" (to varying degrees in
different countries), and incidental inclusion, such as art printed on the
t-shirt of a person that is the actual subject of the picture (subject to the
court's whim).
Going into a gallery and taking a photo of a copyrighted painting does not give
you the right to publish the resulting image. In fact, if you did a good job of
just reproducing the painting, you may not have any rights at all to the result.
-- daniel