A few tips on identifying fake pics.
First, if you think it's too good to be true, it probably is. If the picture show's a girl's face and she's gorgeous, chances are it's not actually her. Use google image search and you'll usually see that the ad just stole the pic off of some model's twitter or instagram.
Take a look at what kind of pictures they are. If it shows the girl in a lot of different places, in different outfits then again it's probably not actually her, just someone's pictures on the internet they stole. If the pictures look like they were taking by a professional photographer for a photoshoot, then it's also not likely they're real. (Well, it actually depends on who the ad is posted by. If it's by one of the larger agencies, like Covergirl Escorts, Carmen Fox, or West Coast Angels, they probably aren't fake pics because those agencies actually do hire photographers. The pics will be photoshopped a lot though. On the other hand, most asian massage parlors or new indepedent girls do not go out and get a photoshoot done, so those ones are more often than not fake.)
After you see someone that catches your interest, do a little bit of research before you book. Again, google is your friend. Search for their picture, see if there's any hits. Search their number online, see if they have a website or if they've posted other ads on other places. Come over here and search for the last 4 digits of their phone number to see if they've got any reviews. Use some common sense and just be careful for red flags. If you see another ad with the same number but different pictures, that could be suspicious. If you see the same picture used in ads from different parts of the country, then that's also suspicious.