[jandrese]

Isn’t the whole point to switch to a palleted image when you dither? If you are leaving it truecolor it just makes the image worse for no benefit as the article noted. Switching to a palleted PNG however can save a lot of bits in certain circumstances.

That said just pulling out a good lossy encoder makes a lot more sense most of the time. It is easier and it will look better. Dithering is lossy anyway.

[munificent]

Yes, you definitely want a palettized output format. But, even so, dithering makes that harder to compress. You're essentially adding noise, which confounds data compression.

[xtracto]

Right, it sounds to me that people are confusing Dithering with Compression. Back in the day we used Dithering to represent high-color-depth images in lower-color-depth devices... it sounds similar to compression but it is not.

It's like confounding stenography with cryptography. In a way, both are used to "hide" a message, but they are completely different beasts.

[riidom]

Yes, exactly. Indexed PNG makes for really small files. Especially when you don't use much colours (for 256-color-index, the saving is not really there, but if you are like <8, it's worth it - if the image fits, style-wise, of course).

[hunter2_]

Yes, just like audio software can dither when reducing the bit depth (say, from 24 bits to 16 bits per sample). It makes quantization less perceptible, by decoupling the quantization noise from the signal, which sounds less crunchy (audio) or has less posterization (images).