A kind of legal question about photos.

[John Beaman]

I am sure there will be further commentary about this from our UK friends, but, in the USA, "public domain" means it is not copyrighted and you can use it as you please. On the other side, if you use it in a copyrighted publication, only THAT reproduction, in your book is copyrighted, not the photo itself. I.e., I could not copy it from your book, put that in my book, and claim a copyright in my book, but if I had my own original reproduction print, I can use it in my book.