NixOS is kind of like that, the image being the environment you end up with running the system. Difference being you tend to edit the source code of small programs passing/transforming data, package manifests and definitions in NixOS, instead of using the "Inspector" to find and browse live Objects of the image/system and figuring out what comes from where, then running things in the REPL to edit them into the right shape with imperative commands, or use the little widgets to enter/edit data.