How dithering works regards to size reduction

[Tom_Durand]

Hi,
I wish someone can explain how your dithering options work, because if the point is to reduce size (for LQIPs in my case) then the point is quite quite missed .
See this image, 400px wide, 54kb:

applying the defaut dithering produces:

Artifacts aside, the size becomes 88kb. How does this work ?

Thanks

[bwintx]

I think the feature is intended just to provide this effect, which had been requested for “look-and-feel” purposes, rather than as a means of reducing delivered image size.

[jmooring]

Dithering an image may or may not increase its file size. The two concepts are independent, with the latter obviously affected by compression algorithm.

One dithers an image to improve visual quality when reducing the palette. The classic example is a color photograph printed on the front page of your monochrome newspaper where the palette is 0 or 1.

In the context of displaying an image on a web page, the images.Dither image filter is, as @bwintx describes, useful for “look-and-feel” purposes.

In the context of printing an image, dithering can be useful/required to achieve optimal image quality. This is dependent upon the printing technology used and available inks/toners.