What were you afraid of? I would assume having to have a detailed map would be the difficult part (I know my lousy home Internet connection always left me hesitant to load the maps, as big as they were) and not so much being good-looking. What is it that’s worrying you, maybe it’s not a big deal?
ETA: And as the GM, you can run your game however you see fit, don’t forget that.
The long and short of it is that I’m really not well versed in Paint.Net, and creating a map takes a good deal of skill in layers and masking, of which it should be noted that Paint.Net does not support masking under ordinary means, so work arounds have to be made, only more difficult in that I’m not exactly making a map of land, per se.