Unit icons.

I'm working on a large mod that involves upscaling, re-coloring textures, and replacing faces while preserving the original models.
The textures are all ready, but I'm facing an issue with the icons. Currently, the only idea I have is to take screenshots and manually crop them.
The problem is that the in-game lighting overexposes certain areas of the textures, resulting in a messy outcome.
Does anyone know a simple and straightforward way to create 170+ icons?