The Plugin Site

I am looking for a plugin that changes a black and white image to color based on the different shades of grey in the original image. I think it was originally used by astronomers to get small details from their photographs.

thank You!! That is it!
Your example was right on the money. I use Irfanview and GIMP which can use Photoshop plug-ins. But I didn't know what to call it.

Thanks again.