Fractographer is a program to plot the fractals of mathematical functions. It can take any arbitrary formula you input, so long as it follows a few guidelines. You can then save the current fractal to an image of any size you want, or you can just save the current formula for later use. You can also use as many colors as you want, and set what bounds they will use, as well as different interpolation levels. More specific information is found in the included readme.
Sample fractal images