Origin is a record, not a visual impression
An image can look photographic and still be generated, or look synthetic and be a heavily edited photograph. Provenance is about connecting an asset to recorded events, rather than inferring its history from appearance alone.
Capture the context you will need later
Define the generation information your application should retain, such as an output ID and model version. Create an opaque reference, embed it, and save the returned watermark ID with those records before publishing the output.
Keep the claim narrow
Recovering an identifier gives you a reference to investigate. It does not validate the truth of every field in your records. Your generation service, access controls and record integrity all influence the reliability of the resulting provenance workflow.
Plan for incomplete evidence
A missing signal is not proof of human authorship. A transformed image may no longer yield a usable identifier. Build an explicit inconclusive state into any interface or decision process that uses detection results.