Actually, either would be reasonable reasons... though if insurgents are suspected as being nearby, or a high-risk target is in sight, one would hope the soldiers would be a touch more vigilant.
Judging from the design, I'd guess it is a meeting area, likely a school or kibbutz-type setup. High chance this is a posed photo, due to the lack of -anything- within the building behind them. I have a friend in LSA Anaconda who constantly complains about his mates being requested for photo ops or spending sprees, though it is just as likely the photo was taken by a journalist tagalong (in which case they would usually avoid dangerous areas and stick to photo/psi-ops locations).