One of many general rules of thumb . . . if a photo is an official US photo (USA, USN, USMC, USAAF, various civilian agencies, or what have you) and so marked, or if you can find the same, not similar, but the same, photo in various national archives repositories, then the photo is in the public domain and may be used without fear of copyright infringement. This would include such described photos that someone else may have, for whatever reason, decided he or she wanted to copyright. Despite what some purveyors of photographs might think or say, you cannot copyright a US government photo.
A US government photo is considered to be a work of the United States Government, which are specifically described in the US Code:
From Title 17 of the US Code, Copyright Law of the United States
"Section 101 - Definitions
. . .
"A 'work of the United State Government' is a work prepared by an officer or employee of the United States Government as a part of that person's official duties."
. . .
NB: "Officer or employee" includes civilian, military, and naval personnel.
"Section 105 - Subject matter of copyright: United States Government works(35)
"Copyright protection under this title is not available for any work of the United States Government, but the United States Government is not precluded for receiving and holding copyrights transferred to it by assignment, bequest, or otherwise."
Note (35) allows the US Government to acquire copyrighted materials and place them in the public domain.
"(35) In 1968, the Standard Reference Data Act provided an exception to Section 105, Pub. L. No. 90-396, 82 Stat. 339. Section 6 of that act amended title 15 of the United States Code by authorizing the Secretary of Commerce, at 15 USC 290e, to secure copyright and renewal thereof on behalf of the United States as author or proprietor 'in all
or any part of any standard reference data which he prepares or makes available under this chapter,' and 'to authorize the reproduction and publication thereof by others.' See also section 105 f of the Transitional and Supplementary Provisions of the Copyright act of 1976, in part I of the appendix. Pub. L. No. 94-553, 90 Stat. 2541"
And in international law, from Berne Convention Implementation Act of 1988 (adopted 3/1989)
"Sec.12 Works in the Public Domain.
"Title 17 , United States Code, as amended by this Act, does not provide copyright protection to any work that is in the public domain in the United States."
A simplistic reading is that photos taken during WWII by members of the Armed Forces or any employee of a civilian US government agency whose duty was to take photos falls into the public domain. Also, any photos for which the Secretary of Commerce has secured the copyright in the name of the United States can be in the public domain if he so designates.
One should take care, though; just because Seaman Jones went out and snapped some pictures of a crashed enemy airplane doesn't make that photo public domain. Seaman Jones has to be assigned the duty of photographer and, generally, the photo used in some official way, even if only to create a photographic record for file.
For example, I have photos of the pilots of at least one USN fighting squadron in both off duty and on duty moments. These are just snap shots that were take in candid moments . . . probably with a trusty brownie camera. None of these are in the public domain. On the other hand, I've photos of the same pilots all lined up for official group photos. These were taken by some photographers' mate or striker and are official USN photos. They are clearly stamped "Official US Navy Photograph" in the back and are, thus, in the public domain. I can copy and distribute them to my little heart's content.
I have pictures of a well-known WWII USN Admiral having a discussion with King Neptune at a line crossing ceremony, no doubt discussing the fates of certain members of his staff. These are little 3x3's, (another key, if you're dealing with an original photo, non-official photos from the period tend to be small) obviously candid, and obviously taken with a personal camera. So, unless someone can come up with the negatives, they may be the only of their type in existence, in which case I could copyright same if I so wished. But, as soon as someone comes up with the negatives, I'm out of luck. (Actually, I suspect I have the negatives around here somewhere, I just haven't found them, yet.) I'd also bet that in some hidden box in the National Archives there's a bunch of similar photos, but not the same ones, taken by the ship's photographer at the same time in nice 8x10 glossies. Pinked (saw-toothed) edges to the prints are also a dead give-away for private vs official photos from the WWII era.
So, if his commanding officer says to Seaman Jones. "take your brownie go out on the flight deck and take a picture of each and every one of our squadron planes." Now, because he's been ordered to do so, that becomes an official duty and thus the product is an official photograph. What would probably be the clincher in such a case would be the use of the ship photo lab to process the film and make the prints.
One thing to remember is that up until the last months of the war, casual snapping of photos, especially of combat equipment such a airplanes, tanks or ships, by non-photography rated personnel was actively discouraged for security reasons.
So, what if Seaman Jones whose duty assignment for the entire war was deputy to the assistant to the chief of the head (having nothing whatsoever to do with photography) goes out on his own and takes the same photos and throws the roll of film in his duffle bag? After his discharge in October 1945 and he's home in Bumscrew, Texas, he has the film developed by the clowns at the local drug store. Those pictures, then, are his, not the government's, and are, therefore, copyrightable. Truth be known, there's not a whole lot of those floating around, mostly due to the efforts of the "we don't like folks taking pictures of what we're doing" security watchdogs.
Bottom line is that you need to have a fairly good idea as to the source of a photo. Generally, if you looking at a photo of a US aircraft or ship and it is of high quality and well composed, it is probably an official photo. Too many folks collect photos and then try to pass them off as their own copyrighted material, but, again, an official US photo cannot be copyrighted. The correct way to handle accreditation if a photo is from a private collection is to say something along the lines of "from the collection of so-and-so," but not "copyrighted by so-and-so". A rapidly emerging trend on the internet is to link to a photo or, if posting a copy made from another web site, is to merely cite the website of source and let that individual worry about copyright problems. I wouldn't do that as it does not absolve you of any responsibility. The law would simply observe that you were apparently aware if a copyright question, otherwise you would have not have taken the action you did, and actively sought to avoid your responsibilities.
If an individual wants to sell you a public domain official photograph, he certainly can, there is no prohibition against it. People and organizations (even the US government) do that all the time. He simply cannot say that he holds the copyright to said official photograph. What you're paying for is time and effort to find the photo in one of the various archives, buy a really good copy from the government and then reproduce it for public sale . . . plus what he thinks you might be willing to spend . . . not a copyright.
If you know for an absolute certainty that a photograph is an official US photo, then you may use it at will. Someone may say they hold the copyright, but if it is an official photo, then it is only copyrighted in his own mind and not in the mind of the US government, nor the courts.
Rich