A FRACTAL is an image generated by a mathematical formula. It has the amazing property of being almost - but not exactly - self-similar at all levels of magnification. Fractals are remarkably similar to natural structures like trees, mountains, clouds, snowflakes, lightning bolts, crystals, etc.
Sometime around the year 2000, I found a fractal generating program that downloads for free. It's called GF4 and it was created by Peter Pawlowski. All of the images shown below were generated with this program. The pleasure of using this program is that it generates several different variations on the basic Mandelbrot set and allows you to easily zoom in on any area of the fractal, repeatedly. At any point in the image-generating process, you can colorize the image with a very simple yet powerful palette of colors of your own choosing. I've been using these images to decorate my CD covers ever since I discovered the program.
If you want to learn more about fractals, try this Wikipedia article.
A bit of Googling will quickly lead you to a huge resource of fractal images and free software programs. In the meantime, enjoy the journey through my fractal gallery...