GIMP Plugin Registry

Radical Image Optimization Tool (RIOT for short) is a free image optimizer that will let you to visually adjust compression parameters while keeping minimum filesize.

It uses with a side by side (dual view) or single view interface to compare the original with the optimized image in real time and instantly see the resulting file size.  read more »

This script is meant to cut an image is smaller pieces and save these images automatically based on the size and names of specific layers, images to be used in web layouts.

Other options I found are based on guidelines. This approach has 2 drawbacks for me :  read more »

This script creates a new image with a window useful for web design.

To install this script, copy it to your scripts folder, then restart Gimp. If you don't know where your scripts folder is, then go to Edit > Preferences > Folders > Scripts.

To run this script, select File > Create > Website Window.

Feedback is appreciated, and I will consider any changes that you request.