layer

This script-fu makes a sky with millions sparkling stars in a new layer. The layer's dimensions, the star's spikes' length and the flare intensity can be changed. The script is based on this tutorial.
This script is useful for create Space Art images, because the stars are convincing.
Good creating !

This is a simple python script, which creates spirograph type curves. There are endless varieties which can be generated. There is a page on my site with some documentation:

http://www.andyshelley.co.uk/gimpfarris/index.php

This is a simple script to invert the brightness of only the dark sections of a picture, without changing the colour. You can change the threshold for the script, so that it creates a brighter picture, or one that isn't as bright. The effect is applied on a separate layer above the active one, so you can delete it or apply a layer mask to it if you want.

Automaticly copies the image and insert this. The script creates a Layer-Mask and makes a part of the insert layer invisible.
It's great to have a part of the original image on the top, because than you have a very well comparision.

If you have any suggestions for improvement contact me.

I hope this example conform your requests:

The script adds an "Extend to Image Size" command under the Layer Menu which will scale the (visible portion) of the active layer so that it has the same dimensions as the image canvas.

http://www.freeimagehosting.net/uploads/8d272dbad9.png

If there is a selection when the script is run, the selected region will be "protected" from scaling and only the (visible) regions of the layer residing outside the selection get scaled.

This script generates two difference layers from the two layers on the top, A is the original image layer, B the modified (e.g. sharpened) one on top:
A - B = C
B - A = D
A - C + D = B

It's similar to GIMP's built-in Grain Extract/Merge function, but the tonal range is bigger.
Now you can apply further editing and "switch on/off" the differnce by switching the visibility of the subtractive and the additive layer. Also you can change the modification intensity by changing the opacity of these two layers.

This script cycles through layers making the active layer the only visible layer (useful for hand-editing simple animations) similar to Layer > Stack > Select Next/Previous Layer.