grayscale to 2-tone random dots
 

there is a method to convert grayscale to two-tone (e.g. black and white) using randomly placed dots, modified to have darker and lighter areas, using dots all exactly the same size and color on a background of the same color (opposite of the dot color).

here is an example result of this method (731,903 bytes 1920x1080 HD/2K)
http://ipal.net/dots.gif

does anyone know what this method is named?

Dithering? See this page for an example of what I think you're referring to. I remember the Wall Street Journal using this to render images of whoever was being featured in some page 1 article.

Dithering is built in to Gimp , it is under
Color/Dither

There used to be a website that featured old time technology that let you select a version with dithered images for those with a slow internet connection, can't remember the name off-hand.

Edit: Lowtechmagazine dot com

Yes! that's the name. i bet a search on that word will find tons of results. having the correct name helps a lot. thanks rnturn!