man
Actually I did answer it: "It started that way then everyone figured they could post pictures anytime and just ignore the rules". I originally allowed externally posted photos. And to Brent's point a lot of members don't really get the whole external posting concept. Most individual hosting packages also provide some space for storing pic on a server but many don't understand the technical steps needed. Instead, I made a decision early on to pay for some storage to make it easy for members to add pic to threads. I think it was the correct idea, but I'm always getting request for more space to post on threads.
Their is a third party package that would allow me to set up a ebay like classified area, including payment management. Just seems like a lot of work for little return and the possibility of a lot of headaches.