When taking a picture without any connection, nothing happens. No popup alert that the file was not sent and that a task was stored into the app to sync later.

It's what the previous native app did.

If it's too long to implement (as it deals with file and sync for this doesn't seem ti be implemented yet), in case of no connection, display straight away a popup saying "This feature is not available in offline mode." Then push back this issue for 1.3.