Anyone know if there is a way to switch image size used based on device detected or media query?

If yes, suggestions how to set this up?

Hello,

This can be done on your overrides.
You can use the srcset method which has a really good compatibility with modern browsers.

Here is a starting point
github.com/kricore/Advanced-templating-with-K2/blob/master/_inc/cheatsheet.php#L126-L145

More on overrides can be found here:
getk2.org/documentation/tutorials/174-templating-with-k2-and-the-concepts-of-sub-templates

Thanks a lot! Worked fine!

You 're welcome :)