There used to be a few "verified" ads but it was an optional feature.  I don't believe Eros ever required that a provider prove her photos were accurate.
But Eros used to make it easier to keep track of the fakes.  They used to have more descriptive URLs for the photos - remember the "Cassandra" crew?  Now the URLs have numbers and it is more difficult to keep track of the fakers.  I suspect it is because they don't have any interest in keeping the fake picture posters off of their site.  It's not their problem.