Hey Sgt Dan. The ones that are not in the VASL folder are a much higher resolution, so you could print these on a larger paper size and not hurt quality.
This sounds fun. I want to stress that I am NOT a VASSAL-izer but a guy who likes to make the graphical maps. I am not going to be the guy who programs the image to work in VASSAL according to their XML specification.
So if you want to continue - let's talk about it a bit more and see what sticks!