Dave: I actually get that question quite a bit. It's not that they're taking pictures of the aircraft, it's what is in it, being loaded or coming out of the aircraft that is in question. Even with a zoom lens on a digital camera can see right into the hold if it's open. We're a lot closer than it really looks to the AF side.
Now it USED to be ok for someone to take a camera phone or a digicam and snap away, but the SF's recently informed us to politely prevent anyone with any camera pointed at the base getting a pic.
Ed: Yes there are "NO PHOTOGRAPHY" signs posted.
Generally if someone gets out of an aircraft and wants to take a pic of his/her family/friends next to the plane, that's ok. Just as long as the base is out of the line of sight.