As has been said, dithering is something that people did back in the bad old days of 256 (or 16!) color palletized displays. It is a way to "fake" more colors than available. It was never meant for image compression.
I don't even remember the last time I saw a dithered image anywhere on the internet.... it's been quite some time.
I don't even remember the last time I saw a dithered image anywhere on the internet.... it's been quite some time.