Wipe that smile off your face. You have not plumbed the darkest
depths of Book Hell until you have set about trying to find out who
owns reproduction rights to the photographs you want to include.
(This particular annex of Hell is named “Permissions Hell.”)
This has only got worse with the rise of the Internet, where nobody
attributes or acknowledges anything. Now you see a cute photogrpah on
the web, decide to use it in your book, and set about trying to find
out who owns the copyright. Lots of luck.