I'm really not sure what I think about this Dear Internet letter from public.resource.org.
They've screen scraped the Smithsonian picture library and uploaded the images to Flickr. They've had legal advice that the Smithsonian's prohibitions on reuse were not valid, and state that:
This is not to say that the Smithsonian cannot obtain funds through creative means, only that the Institution should be cognizant of a special and unique status under our laws. One has only to look at the thriving Smithsonian Associates program or the wildly popular Smithsonian Folkways music site to see that there are many options for government entities to creatively raise funds. Privatizing the public domain is not one of those options.
An interesting issue. I suspect that there will be a growing band of people who don't think it's right to be able to claim exclusive copyright on a scan of a work that is decades out of copyright.
Museums are entrusted with looking after national heritage/art collections, and making these accessible to the public. Should that include making them 'digitally accessible', by releasing digital copies of the works under the same copyright conditions as the original works themselves?