See this page for more details about how the Mandelbrot Set images were produced.
As with other Galleries, this one is not intended as a finished collection of art work, but just a set of images for an investigatory sketchbook.
The early images (which often contain "whirlpool" shapes) are in fact a single descent into a smaller and smaller region of the Mandelbrot image plane, illustrating the "self-similarity" of the figure on different scales (a fundamental and interesting property of the Mandelbrot Set). I then started to look at other colour encodings in order to produce less unsubtle results. I find the later images more pleasing for that reason.
Reviewing this series, I find that I have selected many of the images to have superficial similarities with astronomical objects (such as spiral galaxies and solar prominences). It was not a conscious process at the time, but clear in retrospect.
I also think that I need to work on the colours: something less contrasty would be desirable, but so far I have not yet managed to achieve the effect that I wish.
At present, however, I am looking in a different and more mathematically challenging direction for my next sketchbook. (I will probably come back to Mandelbrot images from time to time as a guilty pleasure when other lines of work are proving not such an easy score.) I shall probably investigate the potential of the related Julia Sets first. (There are also many examples of images based on Julia Sets around the Internet as well, but well, it is still a basic fractal technique that needs to be learned.)