I'm curious though; what would the topic of the next tutorial be?
Anything you think you'd need.
I don't know what might help the most next.
One piece of help I could really use at a distant future stage will be animating gifs. Can that be done in GIMP?
Animated gifs are pretty easy to do in the Gimp, actually.
One animated gif I did in the Gimp can be found here:http://www.sfu.ca/~dvanhumb/cmpt363/images/working.gif
It's an animated progress bar for those times you don't know how long it'll be until done (usually called an "indeterminant" progress bar).
If you open it up in the Gimp, you'll see that each frame is shown as a single layer, with the bottom layer shown first, with the one above it being next.
When you save your multi-layered image as a gif, it will ask if you want to create an animated gif, then ask various parameters for it, including the amount of time between frames (I think it's in milliseconds, and there are 1000 milliseconds in one second), and if you wanted to give each frame a different delay, etc.
Quite powerful, and no additional libraries are needed for that one.