Modifying default srcsets for responsive post images

Hey guys,

Is there a way to make custom size attributes for responsive post images?
E.g. when you use a gallery-window the images are usually pretty tiny, yet the tiniest version delivered is always 600w. Even though the images are sometimes way smaller.

I haven’t found any documentation on this. Am I missing same flag, that makes this possible?

If not, would it be wiser to post-process the “correct” values for the “sizes” & “srcset” attributes in the theme or write the images as custom html? (Like i did in my website - but it’s difficult enough to edit, enough to make you hesitate to change things or add posts.)

Thank you guys for your help!

URL: Not helpful, since production website still displays a “brute-force” workaround from 2019 -
Ghost-Versions: 3.38.2, 3.42.0, 4.1.0

*Installed locally as a dev build (4.1.0) and self hosted (3.38.2)
*Node version: Node.js v14.15.4
*Database: SQLite3 (4.1.0) + mysql (3.38.2)
*Google Chrome 89.0.4389.8

Errors in Console: none