What alwas works:
1. Open 2d paint in Noggit and go to ADT you want to get minimap for.
2. Make a screenshot with grid turned on.
3. Turn grid off without moving camera and make second screenshot.
4. Put those 2 screenshots on each other, cut them along ADT grid lines and save only the one without grid on it.
Very tedious, but works. I haven't find different, correctly working method yet :X.