Go to tineye.com

The web site keeps track of all kinds of images (not just providers) on the web.  So when a hobbyist says "Her photos had a ton of tin-eye hits" that means that the photos the provider are using are found on many web sites through out the world - that in turn means that the photos are probably NOT a true representation of said provider.

That being said, if a provider's ad has photos that Tineye doesn't find doesn't mean the photos are real, just that Tineye couldn't find them.

So to sum up:
Tineye hits = Bad, provider using a photo that isn't her
No Tineye hits = No guarantees on anything, continue to use due diligence

Also, Tineye has a plugin for Chrome & Firefox browsers that allows you to right click on an image in a web page & have it search the Tineye database with out having to copy & paste anything.

Between Google & Tineye I exclude over 50% of ads I find interesting.

Good luck!

You supply the site with a picture and it tries to see where else on the internet that picture is.  A useful way to find out if someone is running ads with fake pics (like using those for some porn star or some internet modeling site).  It's not foolproof but is very helpful.  In this case, the pics in the ads show up in a number of sites all over the place so they are very likely not be of the girl running the ad.