Changing default container registry from to something else?

Let’s say I want Apps to get images not from registry, but from, by default - how do I modify kubernetes (i assume) configuration to achieve that?
Normally I would modify docker’s daemon.json and add registry mirrors, but since SCALE uses kubernetes for this (in which I am a total noob), and seems to store configs in non-default places, I was wondering what my steps would be then.