Quote:
image recognition
As I understand it, 'image recognition' is more like finding a face or a car in a real life picture.
So, I am not sure the wording "image recognition" fit to your need.
Your request is finding a small picture (icon) in a large one (screenshot) is a vastly simplified problem.
I agree that for the first problem, I would look for a library like "Aforge" like recommended by Dave.
But for your problem, I would simply try to do the program by myself.
It is mainly a matter of scanning the screenshot and find a match of the icon.