I'm not much into mapmaking, but for those who are interested I found a couple of useful things:
1. TurboTop: a small program to make a window always stay on the foreground (useful if you have a hand-drawn map or a model you want to copy)
http://www.savardsoftware.com/turbotop/
2. an AutoHotKey script to change the transparency of a window (it needs AutoHotKey, or you can decide to trust the executable, it works also on Vista)
http://www.howtogeek.com/howto/44915/how-to-change-window-transparency-in-windows-7/
Here's an example of a map I was making (drawing at the left, current minimap in the middle, on the right it's how you see them on the screen with TurboTop and semi-transparent window). So it's much easier to make an exact copy of a map. It should make also easier the work for those who want to replicate Warlords 2/DLR maps . I used IrfanView as image viewer.