Config.url for storage and frontend

Developer help
1

Hey,

It’s my first time using Ghost CMS.
I use it as a headless REST-API for the content of subpages.

  • Newest Docker-Version (installed yesterday) - ghost:4.3.2
  • What’s your URL?
    → Backend: ghost.r2t.danielwahl.lu
    → Frontend: dev.r2t.danielwahl.lu

I changed the frontend-url with docker-compose exec ghost config url to the frontend-url (dev.)
But now, the images in posts and pages are not shown.

Is there any possibility to set two different URLs?
One for the frontend/preview/“View Site” and one for the storage (in my case the ghost content directory).

Thanks in advance for your help