There are several ways to make those for yourself. One way is to open the terrain editor, lay down a spot of land and place that object on it. Use w and s, q and z keys to put the 1 square mile of the object pretty much full of the work window. Then use a snipping app to clip a picture. Save as a bitmap and massage into a 512x512 8bit for your field map. I made a map of the tank town road system that way. Some have made an AHF film flying directly over the field and clipped it from there.
Many of the things in the game are made for you by players and not Waffle.