In RPI Imager v2.x the option to customize local images has been removed.
In order to have image customization you need to have your own "Content Repository".
Starting with version RPI Imager v2.0.2 the files in this repository can be paths to your local files or URLs to locally hosted files.
local_repo.json illustrates such a minimal configuration for locally hosted files and locally stored files.
If you want to locally host your files, you can do so via python 3 one liner. In the directory where your images are, run: