It’s as ineffective and thus nonsensical as the “copyright notice” that typical consumers started to cut and paste into their bios few years back. By using their service, you’ve already accepted their agreement, to whatever extent it’s legally enforceable. I really doubt that it includes a clause that you can negate or place restrictions on the agreement within the content that you post using their service. It would make more sense to send them a letter if that’s really what you want to try to do. If you don’t want Facebook to use your image the best way is to not upload it to them.