The problem with any free message board system is that they only exist while there is profit for the company that owns them. As long as their offer of free services is profitable through ads, or users paying not to see the ads, then they will (may) continue the service. Unfortunately, as happened with the old Association Message Board, it literally disappeared when the company shut down. There were no points of contact for Administrators, and no means to recover the data. That is the risk of "free" services.
The only secure way to collect submitted images and information is to own the servers of have a direct relationship with the company managing them to the degree that it is under stood that you own the submitted data. This should also be done with some small degree of process so that they can be catalogued for future reference and useful as a storehouse of regimental history. Otherwise it becomes just an electronic version of the big boxes of photos in the Museum basement.