Morphological operators on steroids!
An extension to the default set of morphological operators for GIMP: erosion, dilation, opening, closing, boundary extraction, gradient, hit-or-miss, thickening, thinning, skelethonization, white and black top-hat.
Additionally, this plugin lets you define a custom structuring element for operations. The plugin is tested to work on GIMP starting from version 2.6.
Follow the general instructions to install a plugin on GIMP. You will find "Morphological Operators..." under "Filter -> General" menu.
This project costs me a lot of "No, not tonight" answers to the questions "Hey, Ale! Wanna go out with us for some beer?". So, if you are a real gentleman, why don't you pay me back those missed drinks? ;)