[beefield]

I think of it with this kind of analogy: the original image is stored with 32 bit color scheme. You can reduce the color scheme to 16 bit accuracy and still figure out pretty well what the image is about. 2 bit is stretching this to a bit far, basically either pixel is white or it is black, but even if you lose lots of nuances in the image, in many images even that gives you some idea whats going on in the image.

[DougBTX]

That’s an interesting question, I wonder if there is an analogy in quantisation to image dithering?