That's how a gentleman talks!
I know of guys who take selfies in their clients bathrooms specially if they have good lighting.
What a pic with the client's dog?
They can always ask: "Can you take a picture of me?" As long as nothing too easy to identify like previously mentioned family pics, cars, etc. I don't see a problem.
What if they escort is left alone for a few mins during an overnight/weekend when the client is busy doing something else? He can take a selfie within seconds just because the lightning is right or he loves the interior design, pool, etc.
I'm sure one day you'll catch a provider taking a picture in your pool.