This is only partially true, while technically a photo taken by a govt agency is a public document there are several restrictions on the use of said photos. For example DOD photos:philip964 wrote: My understanding is all photos taken by federal government employees are public domain automatically. Copyrights on photos last a long time, so I'm not sure how a photo ever becomes public domain anyway. Micky Mouse for example is still copyrighted and he is pretty old. Just because you can grab it off the internet and it does not have a copyright symbol does not mean it is Royalty free.
Guidelines for Using DoD Imagery
Image Alteration. As governed by DoD Directive 5040.5 (Alteration of Official DoD Imagery), the accuracy or integrity of our imagery must be maintained in accordance with established DoD imaging ethics.
Restrictions on Use. Our products are readily available unless their release is precluded by statute (as in the Privacy Act), by authority (not released to the general public) or precluded by current and valid security classification. The applicable military public affairs office (Air Force, Army, Navy, or Marines) must be contacted to obtain release authority for any non-releasable visual information records maintained in the DVIC holdings.
Talent Releases. Our imagery is provided without talent releases on any individual portrayed. Imagery is provided with the understanding that the DoD has no authority to waive the privacy rights of any individual depicted in government media. And no exclusive rights to official records may be claimed by any organization or individual.
Commercial Endorsements. Users of DoD imagery will not be portrayed by implication or otherwise that the Department of Defense endorses any commercial product or service.