You can configure Concourse with docker URIs for the resource types, and then just keep pushing to the docker registry (or your own private one). Only gotcha is that auth is not supported, so your images would have to be public (or again on your own private registry).
We have plans to support a fly CLI -based workflow to "push up" resource types to the cluster (and guarantee the same image is used throughout the workers, etc). It'll take a while to get there though.