A new flag I've first seen today on a Creative Commons photo page declaring license Creative Commons Attribution ShareAlike v4.0 International:

"This file is copyrighted and has been released under a license which is incompatible with Facebook's licensing terms. It is not permitted to upload this file at Facebook".

In other words - since the license doesn't allow Facebook to take ownership, it is not allowed on the Facebook site. If this photo is not allowed, then NO photos or other works licensed under Creative Commons are allowed.