This has come up a lot locally. People who take pictures while in uniform and on the clock and then say they are theirs. Not so. If you clicked that pic and posted it to IG, it's public domain.
That's not the real issue. The one I know if is a guy who was working on a book. Complicated funding, but a grantor gave the NPS grant money to pay for this person's position to create a book. During the course of it, he took a lot of photos. The librarian's position was that all the photos needed to be deposited with her. He said okay, but he wanted to put them in the book as "Copyright John Doe 2010." The librarian said, "No, that's not now that works. Govt salary, govt camera means govt photos which means public domain."
Lots of employees are not taught that though. 99% don't care and are happy, even flattered, to have their stuff go into public domain and see broader usage. But some get surprised that their "art" is not *their* art. It's the American people's art, thank you very much.