I have the large one (in the pic above) and used it SO MANY times as a diaper bag when my son was little and even though it is the largest of the backpacks, it's not THAT big. What are you going to use it for?
You may want to check out the LV official website for the dimensions of the bag. The small is something like 10x12. The large is something like 12X15, but don't quote me. By the way, when I saw one at the store, the leather drawstring seemed kind of wimpy to me. Has anyone had personal experience with it? I was wondering how durable it was.?