When you take a selfie, it’s probably syncing to one or more online services (icloud, dropbox, G+ …). Whichever company it is, you have agreed to their terms of service.
Some of these agreements are pretty generous about the rights they give the company over your images.
When you stand in front of a CCTV system, you haven’t signed anything, in fact you’re covered by some pretty comprehensive EU data protection legislation.
At least, that’s how it seems to me.
Here are the UK Government CCTV Privacy Guidelines
Here are the (Slightly less readable) Irish Government CCTV Guidelines.
Here’s a great article by Roisin Kiberd on the subject for Vice Magazine / Motherboard.