I have worked with C# (that's C-sharp) a little bit in the past, although I'm no expert.
It looks like it should be relatively straightforward to do what you are looking for, using the code in the linked article as a starting point. That code looks like it returns a bitmap in memory - you would need additional code to write the bitmap out as a file (you might be able to find sample code to do that part).
IIRC you can get a free version of Microsoft Visual Studio that you could use to do the programming. If you have some programming experience in another language, you could probably learn enough to build such a program in a day or two of studying.
For someone who has the skills already, it might take just a few hours to cobble together something that would work, and maybe a few more hours to clean it up a bit and make it more user-friendly.