Gym took photos of member without consent and posted them to private Facebook group

So I won’t be going to this gym for much longer because I’m not well pleased. Without any explanation or consent the gym took photos of me during workouts, and then posted them online to the their member only Facebook group. I joined the gym start of Jan and this has happened on several occasions.

There’s nothing in the gym contract about photos and I did not provide verbal consent. I queried the owner and the only response was “we did ask but sorry if you didn’t hear”. My recollection of what I’ve been asked, and hearing, is good, so I find her to be untruthful. This is in the category of being annoying and I will look for a different gym.

Welcome any thoughts re the law.