A source for US military service photos?

Every member of the US military has an official photograph, and I presume they have been doing this for a while.

I just checked, and the Wikipedia entry for Rick Rescorla does not have an image of this man who saved a huge number of people from the World Trade Center on 9/11 and was killed in the collapse when he went back in to make sure.

There is an image of Rescorla in uniform that looks much more carefully posed than most official photographs, but then he left the service as a Colonel - so presumably they get a bit more care.

The question is - is this image likely to be an official photograph, and therefore created by the US government and possibly free for use on Wikipedia? If so, where would I find it along with the proof of it’s copyright status? Is it somewhere in the National Archive and do any folks here know their way around it?