GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. Even if it is created as Free Software, GIMP works on many operating systems, in many languages.
In 2005, LinuxChix have organised an online course for people who wanted to learn more about GIMP, and they have published the lessons online. The course consisted of 11 weekly lessons.
The main topics were"
Getting Raw Material: Some Sources for Images
Lesson 0: Welcome! Get Familiar with the GIMP
Lesson 1: Cropping, Zooming and Rescaling
Lesson 2: Lightening, Darkening, Sharpening
Lesson 3: Introduction to Layers and Text
Lesson 4: Basic selection tools, and copy/paste
Lesson 5: Basic Drawing Tools
Lesson 6: Erasing Unwanted Objects from Images
Lesson 7: Selecting Complex Shapes
Lesson 8: Text Effects (How to get really cool looking text)
Lesson 9: Layer Effects, including more text tricks
Lesson 10: Stitching Panoramic Images
Interlude: Sources for More GIMP Information
Interlude: Drawing a Circle
The page for the GIMP online course.
On the LinuxChix website there are a number of other courses, such as Programming in C, LateX, Security, Perl, Python, Home networking, domain names, course on how to write clearly or how to run a course etc.