It has been against regulations forever, at least back to Vietnam and probably earlier. So that would fit under Article 92. I don't know of anyone ever charged for this, but this is one of those charges that you would add when more serious charges were being contemplated. As in this case. This one is easy to prove, so it guarantees that you get a conviction. Gallagher shouldn't have allowed the photo and made some other dubious lapses of judgment, but I don't think that he was a murderer as charged.
Some of the witnesses were in the photos too!!!!