OK, I've just added a few new categories, based on what we've seen uploaded so far. It's obvious that national markings under Military Aviation will be popular, so I've created an explicit category for that, along with a few subcategories for what I see would be the most popular areas under that. Any national insignia markings that don't currently fit any of those subcategories can just go in the main subcategory of National Insignia. The same goes for anything related to military aircraft that doesn't fit any subcategory created so far. New categories can always be created as necessary, and files moved to more relevant categories.
I also created another top-level subcategory under Aircraft - Military, called Camouflage Patterns, which pretty much does what it says on the tin. Again, this can be subdivided down the track if demand warrants it.
Note that I haven't made corresponding forum areas for all these new categories, since I don't think that's warranted at this stage. Just as with the categories themselves, we can revisit and revise that in the future.
One thing no one has done so far is provide any screenshots, so I might backfill a few when I get a chance.
Kev