Originally Posted by
Nicks Pics
I use gimp as well, but in my opinion, it makes more sense to use a RAW converter - type program like Lightroom, or one that came with your camera, (or there are probably many other free or purchasable options) for basic editing, such as lightening the shadows, adjusting the colors, white balance, etc. and then if you wanted to try something more advanced with the picture you could use Gimp to do Frank's suggestion about processing the sky and ground differently and then combining them into one image.