Star Trek History, as I understand it, isn't asserting ownership of the pictures their contributers purchased from Lincoln Enterprises. Where they draw exception is the use of their restorations of these images to promote the book on Facebook and in the book itself, which the publisher did without asking permission or (in all the cases I have seen so far in the book, which I have not finished) giving credit to the site.
Gurian has asserted that the images are either his (purchased from Lincoln Enterprises) or that he can't remember their source. Star Trek History has asserted that the "digital fingerprints" of their restoration can be found on the images which continue to be posted on Facebook to promote the book.
I am no expert on photographic restoration, but I trust Star Trek History in this matter. Considering that they would have likely provided their restorations for free (and at much hire quality) if the publisher had simply asked, the behavior of Jacobs Prown Press hardly strikes me as noble.