Back into an OCI image? I don't know if lxc can do that, but podman can. I think it is podman save that allows you to save your current container as an image. Or, even better would be to use buildah. With buildah your expected workflow is to kind of run a container, run a script against that container, then save it at the end. In fact I'm specifically thinking of images I've created with buildah as being almost completely useless with this LXC technique. I've used the RHEL UBI micro image before and it doesn't even have a package manager. You actually mount the container to the host and use the host's package manager to install what is needed and then unmount it to save. It makes a super slim image with as little attack surface as possible.