Just thought I'd throw this in, in case anyone is actually looking. Below is what I call a 'negative' of the image above. Same underlying image, just interpreted differently. In this case, the madelbrot set is shaded in white, and what is not part of the mandelbrot set in black.

Textbook limits here. This shows what a good approximation of the Mandelbrot set should look like. First, (1) outlines a proper anvil-shaped limit one sees between atoms (bulbs) of scale. And (2) is how the pinch-offs separating atoms should appear - drawn out to pixel level, even appearing to just touch. If your limits don't look like this, it means your iterations (bailout, how long the computer will dwell on a given point before assuming it's part of the mandelbrot set) is set too low. See atom #9 for another good negative.

If the number of iterations is too low, you might get something like image below. Note the ragged edge that appears, with the boundary not being tightly defined and portions of it mistakenly counted as part of the Mandelbrot set (the area in white).