This I made for people creating sprite animationes. It can reduce the size for all images to 8 bit indexed without mixing up colors that should stay she same, like backgound colors that are supposed to become a transparent color.
It is my first GIMP script anyway and is a modified version of the sg-save-all-layers script.
It just saves a stack of layers as .bmp files with a palette of your choice in the specified directionary.
Create a palette___________________________________________
If you want to create a fitting palette for all the layers use mode>indexed, but remember not to use to many layers for this, because the calculation will take to long. Only make sure that the most needed colors are on the layers that create the palette. Edit the palette. If a sprite backround is needed make sure there is only one instance of the colortype. Save the Palette with a name you can recall.
(if this does not work make a copy and rename it)
Then run this script.
(tested on win 7)
You can now simply select a palette in the palette menu and select "Use Selected Palette" to create the images using all the same.
Added the "Create New Extention" checkbox, which allows you to avoid double extetion naming when the layer contains a extention already.
Remember that if you do not have any extention you still get an error message.
Added a GIMP 2.611 Version. To get the palette you created like discribed on top you have to right click on the palette menu and import it from the image containing the layers with the main colors.
The 2.611 Version is much faster by now.
You can now browse for the target save folder.
Make Optimal Palette - creates for each single image a individual palette
Use Selected Palette - Uses the in the palette selected in the palette menu for all images
Make Web Palette - makes a reduced individual palette for each image
Make Web Palette - makes a black and white individual palette for each image
Assign Custom Palette - like "Use Selected Palette" but you have to select the palette below
I hope this will be helpful!