doesn't matter if you post photos of yourself online, very likely it will be others that do so. And your image is being digitally captured constantly, if you travel on public transport or go through an airport, or do anything in a public place your photo has been captured many times. Figuring that it's you is also pretty straightforward. All it takes is a DMV hack or Facebook (where one of your coworkers tagged you in a photo, or instagram where your niece tagged you by the bbq on july 4th etc etc etc...