"We can use the GMOME icons on the same basis that we use things
such as oldxlib: saying that they are not part of Emacs, but
used by Emacs and distributed with Emacs."
Exactly where we shall say this I don't know. Is an entry in NEWS
enough?
People look in NEWS for information on changes in how to use Emacs.
It is not a very useful place to put information on legal matters.
We should put them where people would look for them.
The place to put this information is in a README file in the directory
that the image files are in.