Since image recognition should only run on author, tags should be somehow propagated to public instances.

This could be done by publication, but we should be careful about when this is desirable and when it is not. For example a not-yet published asset should not be published just because it received a new tag, but an already fully-published one should likely be re-published.

This behavior could be configurable, and even include user interaction (like a button "publish all tagged assets" inside a pulse notification when indexing is done).