GIMP Plugin Registry

This script simulates a high quality (portrait) photo like these from the National Geographic.
Copy it into the scripts folder from GIMP, you will find it then under Filters -> Generic -> National Geographic.
Thanks to Martin Egger for the shadow revovery and the sharpen script, which I included in the script.
Examples:

This script crops the image so that the current selection winds up at the center of the image. It is especially useful when postprocessing digital images: When the subject of a photograph appears off-center, simply select the subject, click on Script-Fu/Selection/Center Selection..., optionally customize the script's parameters (described below), et voilà—the subject is now perfectly centered.

This script makes a ring system that you can add to a picture of a planet, and was adapted from a Photoshop script. This script is updated for GIMP v2.6
The ring system can be any size from 300x300 to 3000x3000, and can be tilted to any angle. The whirl-and-pinch portion of the script is time consuming, but using at least 8 iterations make the rings look very nice. The thickness of the rings can be controlled using the inner and outer ring ratio values in the script. The closer these two values are together, the narrower the ring.

This script creates escaping lines from any point. It's similar in function to the built-in Line-Nova Script, but much more flexible. So you can chose the center, the thickness, the angle, the length, the offset and the randomness.
Copy it into the scripts folder from GIMP, you will find it then under Filters -> Render -> Escape Lines.
Example:
http://www.flickr.com/photos/28653536@N07/2868527851/

A simple script to emulate the sepia toning ; it is an automated
version of what can be found in http://gimpguru.org/Tutorials/SepiaToning/

This script simulates a yellowed and slightly jagged border like these of old photographies.
Copy it into the scripts folder from GIMP, you will find it then under Filters -> Decor -> Antique Photo Border.
Examples:
http://www.flickr.com/photos/28653536@N07/2842947808/
http://www.flickr.com/photos/28653536@N07/2863559734/

This script allow to offset n x m times the active paint-brush.

Tutorial: http://xoomer.alice.it/lwcon/gimp/script-fu/draw-offset-point.htm

This script simulates the 3 Color Technicolor effect.
Copy it into the scripts folder from GIMP, you will find it then under Colors -> Technicolor 3 Color.
Examples:
http://www.flickr.com/photos/28653536@N07/2853315748/

This script creates small rectangular selections and auto-white-balances them.
Copy it into the scripts folder from GIMP, you will find it then under Filters -> Light and Shadow -> White Balance Puzzle.
Be careful with the feather option, it consumes a lot of cpu power.
I use it more as an analysis tool for existing images. You can detect edits in low contrast areas with this script.