[Dominik]

Chris the example you have given is something else. I assume the photos were taken directly from your book which is copyrighted.
But if I buy a photo from any source and the photo belongs to public domain I do not have to pay extra fees for publishing. But if someone who owns the photo shares it with me it clear for me that I should ask for permission (I always do that). If I were them I would have asked you first and then publish on the website.
Returning to main topic. IMHO museums shouldn't take extra fees for the right to publish materials from the Second World War as it's a public domain. In Australia it works like that and in the States too. So why is the difference?