Unit icons.

I'm working on a large mod that involves upscaling textures, recoloring them, and replacing faces while preserving the original models.
The textures are all ready, but I've run into an issue with the icons. Right now, my only idea is to take screenshots and manually crop them out.
The problem is that the in-game lighting overexposes certain areas of the textures, resulting in a terrible mess.
Does anyone know a simple and reliable way to create 170+ icons?