I have found out that one caregiver has videotaped another aide while working (why? I don't know), and it is possible that she has take photos of the house and may share with other people. This seems wrong to me and wonder if anyone else has dealt with this. With smartphones this must be an issue. I'm not sure this aide is working out anyway, is there any way I can make sure she doesn't share any photos with others? She is often alone while caring for mom with dementia, so I haven't seen her do this, but have been told it happened.
Whoever is taking pictures needs to stop until you or your father give them permission.
They could just be trying to protect themselves, too. If they observe something and need to show their manager, to make sure something is documented.
Find out why it was done, go from there.
And also, why not put a remote-viewed camera in plain sight in most commonly occupied room? (Not bathroom or anything private, just living room.) Whether you actually view it or not, you give yourself the option... just in case.
Check the contract someone signed to make sure there's no explicit clause allowing this. And call the agency and share your concerns. They should respect your wishes, check the aide's phone and delete the photos.
But unless there are issues such as CM suggests, I would consider replacing that aide. You don't know what else she might have photographed or where the photos will end up.
Personally, I find this trend toward photographing literally everything, anywhere, any time, to be not only offensive and tasteless, but irrelevant. I don't understand why people think so many photos are necessary, especially the silly selfies. Don't they know what they look like?
Taking pictures of your client or your client's home without your client's explicit consent is bang out of order in any case. But if - IF - this were being done to expose poor practice, or defend herself against an accusation of bad practice, or for some other well-intentioned reason directly relevant to your mother's welfare, it doesn't have to be a firing offence unless you choose to make it so. But you do need to get to the bottom of the matter.