I just came across this cool effect (in the linked article) whereby hovering over an image changes it to color. In this case it’s just a silly novelty as the unhovered presentation would use copious black ink. But apparently this technique /could/ be used to create a page that loads fast using small bilevel images. The images could be dithered with printing in mind in a way that minimizes ink/toner consumption. The color varients of images would of course be the last to get fetched. A well designed server could even give an extra low priority to the color variants when traffic is high.
You can just use a print-specific stylesheet.
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