This will sound odd but I’ve found one of my pictures used by some guy on his website. It was happen a few years ago. My bad, I didn’t keep any print screens of that.
But why on Earth would someone use your picture instead of his? For the simple reason of not using personal pictures on internet. Well, I can’t tell why is not just renouncing to use any picture on it’s profile.
To find out if someone is using your picture on his profile check this website, using reverse image search. Is free to use and might return some unexpected results, so don’t be too much confident that you’re out of grid.
This is the website:
Reverse Image Search
Hint. You can go even further and look not only for pictures of you but other picture taken by you. You might find some of these used without your permission on others websites photo galleries. Tough eh?