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I promised, so here's how to write the GIMP plugin for generating a throbber. A throbber is basically an animation like this one:

It is a GUI widget that conveys the user the notion that the computer is not hung up, but otherwise busy doing whatever it is told. In the web, you've probably seen it in your browser, on the top right corner, whenever the browser is waiting for pages to load. But then, ajax came, and the browser throbber does not convey all information anymore. If a page is requesting an update for a given element, the browser won't tell the user it is loading anything, so it is up to the page developer to do so. GMail uses a small red progress bar on the top right corner. Others use throbbers, mimicking the current browser behavior, shown on the page element being updated.

GIMP can produce animations, using images, with multiple layers, saved in GIF format. Moreover, it is completely scriptable. Any action you can do interactively in the editor is available via scripting. It is scriptable in lisp and, more recently, in python. I'll use lisp. On uber-geek karma, lisp beats python by a huge margin. The geek adulthood trial is the implementation of your own personal lisp interpreter.

It's late today, so I won't take time out of my sleep to write the tutorial. Tomorrow, however, I'll write up on how to create a gimp extension, summoning the powers of script-fu to create throbbers -- those useful little animations used in ajax apps.

Today, I'll only show the end result:

And the screencast on how to get there (click to start the animation):