I don't know, but I suspect that many of the
images that are PD-UK would
be useable under fair use in the USA. If so would it be possible to use a
dual licesnse along the lines of "This images is public domain in the
United Kingdom and other countries that use death+70. In the United States
this image is contended to be fair use because of xyz" ?
Images are never "fair use" on their own. Specific uses may be fair, for *any*
image. There's no such thing as a collection of fair use images, by definition.
-- Daniel