Most of the Asian ads use fake pictures. It's easy to tell right away or if you're in doubt then do a google reverse image search to see if you turn up with anything.
Some of the Korean ones use their real pictures but they're very heavily Photoshopped that it's practically not even the same person anymore.
The best you'll get will be the ones who you see holding up a sign with "ERS" or "Leo", and you'll be able to tell that they're probably real.