GIMP Plugin Registry

This script changes a rainy landscape to a sunny one.
Copy it into the scripts folder from GIMP, you will find it then under Filters -> Light and Shadow -> Sunny Landscape:
http://docs.gimp.org/2.6/en/install-script-fu.html  read more »

To fix burned out or white skies by adding clouds and a blue sky gradient (using a threshold mask).

Guide to Using the Blue Sky & Clouds Script  read more »