From clicking around this site, it looks like their image dithering technique has taken away the color quality required to properly view the graphs on this article: https://solar.lowtechmagazine.com/2015/10/the-4g-mobile-inte...
I'm not convinced it saves much in the way of bandwidth, either. If you take this[0] image, it's 43 KB for a 800x533 image. I'd expect a JPEG to be able to do that without too much in the way of artifacts. It does give the page a kind of neat newspapery vibe, though. [0]: https://solar.lowtechmagazine.com/dithers/sps_wide.png
I tried testing some variants and made a static HTML gallery on neocieties[1]. TL;DR:
- cleaning up the photo before filtering it makes a huge difference in image quality and compression.
- quality 80 JPG is 86,6KiB in color, 70,9Kib in grayscale.
- quality 40 (which is ugly but still has readable text) uses 44,8KiB and 37,8Kib respectively. The latter looks a lot better than the dithered image IMO.
- similarly, the grayscale PNG with pushed shadows and positioned dithering has readable text and contains significantly more detail at 4 colors and 38,7KiB than the 16-color 42,4KiB image on their server.
[0] http://www.lowtechmagazine.com/2018/09/how-to-build-a-lowtec...
[1] https://blindedcyclops.neocities.org/low-tech-image-tests/ga...