Making the app and the validated content files editable is actually the next major feature. Once we conquer that, its onto making it work for live content.
We haven't started that phase of development yet but the original image would still be immutable. Subsequent edits to the image metadata would be would be done via Photoshop with a plugin for tracking those edits and then saving and certifying that the original image was still locked with the added visual changes. Haven't decided how those additional changes would be tracked, but I'm guessing it's necessary to do so.