To the best of my knowledge, fractal images are generated mathematically
using fractal geometry. Different mathematical equations generate different
fractal images eg. 'The Mandelbrot Set' which, I think, appeared on 'T'
shirts back in the 80's. Unfortunately, my email software does not have the
capabilities for me to write the mathematical equation here. Suggest
looking up Mandelbrot Set in Google. There are many books available on
fractal images.