Image sizes in Docs

[dkastl]

I saw, that a (few) image(s) in the docs are not so small despite jst being screenshot(s).

There is an interesting tool to play with formats and image settings: https://squoosh.app/ Could be, that Mkdocs already cares about image optimization, when the static site is built, otherwise we could try to not make images bigger than necessary.

Not urgent, just a reminder.