Based on the analytics at a startup I used to work at, photos are a much better driver of user engagement than status updates. I'm guessing the same is true for facebook, and anecdotally, most of the facebook comments I receive are on photos and shared links, not status updates.
If the status update is mundane like "am eating a bagel" and you have a really funny photo of eating a bagel then the photo is definitely going to win the comment competition. If you use the status update intelligently, like tweeting about something that will interest your group then you can have a good discussion going on with just a few simple lines. Like a Tweet on FB Wall.
