does somebody know how to cache images from storage in-app? is it only possible via e.g. localstorage or is it even possible server side?

I've used localForage for years. Simple interface and uses indexedDB so not as limited as localstorage. Handles files directly also. I use it now with Supabase as part of my offline solution to store uploaded user files until back online to upload to DB. https://github.com/localForage/localForage