Related—I wrote a novelty dithering Mac app and released it this week. It dithers photos and converts them to MacPaint format for display on old black and white Macs. As another commenter pointed out, dithering was less about compression and more about just making things look okay on the limited displays of the time. The original Macintosh had only black and white pixels (no grayscale).

Here's the app: https://oaksnow.com/retrodither/

And here's my blog post talking about how I wrote it: https://www.observationalhazard.com/2021/09/building-retro-d...