(en) To create web page buttons style Aqua Bou - For The Gimp 2.4.
This version is for Gimp 2.4 or higher (with Tiny Scheme interpreter).
For The Gimp 2.2 or lower version (which uses the SIOD Scheme interpreter), I suggest you use the Aqua bou version 2.2 .
Once installed, restart the Gimp and access the menu: File -> Create -> Web Page Themes -> Aqua Bou -> ...
This Shadow&Highlight script does a decent job of lightening shadows and/or darken highlights in photographs. The UI gives you five control sliders. Two for control of the Shadow and Highlight amount (opacity), two for the tonal width of each contrast mask layer (using gamma), and one for the blur radius of the masks. Plus the option to flatten visible layers when done.