I'm pretty sure it's because Facebook started suggesting that Alice should be tagged in Bob's photos without Alice's consent. They're Bob's photos but it's using Alice's likeness to suggest tagging her without her consent.

Edit: And the law in Illinois is (to quote the article): 'The statute requires any entity that gathers biometric data—including fingerprints, voice prints, "hand or face geometry," and retinal or iris scans—to get informed consent from those individuals whose data it collects'