If you take the "4x4 ordered dithering" image, and copy it, use a "mean curvature blur" filter (I used gimp - similarly for gaussian with low enough width) and

If you take the "4x4 ordered dithering" image, and copy it, use a "mean curvature blur" filter (I used gimp - similarly for gaussian with low enough width) and overlay it on the dither at 50% opacity, the image actually looks pretty good. This could probably be done in CSS/JS on a client machine. a 14k image comes across passably, even on my desktop.