I need to load some image files from Cloud Storage. For a given folder I need to check what images (if at all) are available in it. It seems like the firebase client library
The methods to list files in Cloud Storage were only recently added to the Firebase SDKs, so it seems likely that they haven't been ported to the FlutterFire library yet.
You'll indeed either have to implement the interop yourself (in which case a PR back to the repo is highly appreciated), or wait for someone else to implement this feature request.
A final alternative is to not depend on this (relatively new) API, and store the list of file paths/download URLs in another data store, such as the Firebase Realtime Database, or Cloud Firestore.