I think this is more-or-less a case of history repeating itself.
One person - and I name no names, because doubtless everyone knows who they are anyway - is flooding the group's upload system with irrelevant "art", most likely in an attempt to get it noticed, and not only do most of you seem to be getting annoyed with it, my fellow admins appear to be in agreement.
Enough is enough.
I've sent the person in question a message and as before I think a clean-up process is in order - i.e. an attempt to unclutter the group, but for now you should expect no more of this sort of thing.
To be clear; this group is called Call-of-Duty-Army for a reason. It is a place to submit Call of Duty-related art, and just because something happens to be military-themed does not make it appropriate.
My sincerest thanks to all those who voiced their concerns and my fellow admins for their help in resolving this matter.