I have made this short tutorial about how to make a minimap for Stronghold 2. Here is shown how one can do it with Fraps and Gimp, but once one sees how to do it with Gimp - they could do it in similar way using any other image manipulation program.
Download and install Fraps. It's a free program by which you can easily make screenshots in any game. Before the next step attention to what key is dedicated for you to make a screenshot with Fraps. In my case it's Print Screen key, as it was easiest one for me to remember.
Run Fraps, and then run Stronghold 2, and go to kingmaker game, and find your map.
Put yourself in one estate to the left, and then put yourself in another estate to the right.
Leave Stronghold 2.
Download and install Gimp, it's also a free program, and this one is used for image manipulation. It offers a lot more then you need right now actually.
In Fraps you have the View button by which you can open the folder where your Fraps screenshots are stored. Open that folder, open Gimp, and drag those two screenshots into Gimp. Note: Gimp may open a little slow, but be patient, once it's open everything runs smoothly.
Use the cropping tool to crop the minimap from one image, and the other. You can use Control & Mouse Wheel to zoom in and out, so you can do crop it perfectly. Once you select the area you want to crop double-click it to do the cropping. You can use the Mouse Wheel Button too to move around while cropping.
Use rectangle select tool too select one side of one of those minimaps, copy it (Control + C), and paste it (Control + V) into another one. Then you drag it in the right position; you can also use the arrow keys for that.
Go to File/Export As..., go to
Select File Type (By extension)
to choose PNG or JPG.
I prefer JPG, as it loads faster on webpages.
Name your minimap as you will, export it into the folder you want, and that's it.