I once made such a tutorial for Spider but I already removed the file, it had pictures and everything. It's certainly not impossible to make maps in MsPaint and you can even make good ones if you got the skills, like me. I generally dislike maps that are a direct ripoff from the game, but there may be a need to use such a map as a base to make sure it is accurate. Later on you may choose to draw on top of it by hand to make it look original.

Anyway, with the circular maps you must note that the positioning of the towns is not accurate. They will move around by a few pixels so they cannot be used as landmarks.
It is best to save the map in it's full size without starting to resize it because you will lose data when resizing it. When you are ready to publish it, you can reduce size as much as you see fit.
If you have the direction markers turned on, the fastest way of removing them is to create a cutout with a circle that is exactly the same size as the map image and with opaque edges. When you copy map graphics from the game, paste them into the file where you have the cutout. Switch off "Draw Opaque". Select the cutout and move it on top of the round map image so that they are aligned precisely. Now you can flood fill the edges white and you will get rid of the direction markers with ease.

Also remember to flood fill the orange dot white.

Now select the round map, cut to clipboard and switch to your big map file. Do not save because you will need your cutout with every snapshot. (Unless you turn off directions.)
When in your big map file, there may be a need to stretch the drawing area and move the existing graphics so that there is room for the new snapshot. Once there is enough room, zoom in and paste. Now if you have sharp eyes (and draw opaque is still switched off) you should be able to align the map exactly. Don't let it go before it looks good on every size. The maps do align perfectly if you're doing it right. The only thing that distracts you is the town dots, since those will move around.