I think there is a bit of a misconception here about social media pages. If you post a photo on social media it is not private and people copying, saving or using it is not a breach of that person's privacy. The way you can safeguard against people not seeing, using or sharing such photos is not to post them in the first place. This is not the same as taking a photo and putting it on your sitting room wall where you have a reasonable expectation strangers would not see it.
I fail to see how social services essentially using social media (on which people, of their own free will, have posted photos of themselves) as a research tool to obtain information about birth parents for adopted children and their parents is some sort of gross unprofessional act. My son's social worker made no bones she used facebook to try and fine my son's birth father. She had very little else to go on and wanted to have done everything she could to identify/locate him. I make no bones about the fact I have saved screenshots of the stuff birth mum has posted publicly on Facebook about songs she likes, new stories she is interested in, nice things her friends have said about her. She is putting it out there for the world to see, why shouldn't my son also have the right to know something more about her than the brutal, sad facts about why he was removed from her? There is nothing unprofessional about using this information and the idea a social worker should be "disciplined and deregistered" for doing so is ridiculous. It is not like she broke into birth mum's house and took photos off the wall. This stuff is not private if it is put on the internet.
As for photos of birth mum which were provided to us by social services, I would not share those or show them to people (exception being my son's birth sibling's parents) and neither would any adopter I know.
Our Miracle, we adopters are not given things like birth parents' home or work addresses. Even the court documents which the judge ordered social services to provide to us (because they contained nice details about birth mum's contact sessions with our son and how she had shown love towards him and the judge thought my son would want to know later in life) were heavily redacted, quite rightly. So the answer is, barring incompetence, this information will not be shared with adopters. So, really, the way to protect your privacy is to be careful what you post online.
OP, I think you are getting a really hard time and I am a bit confused about why everyone seems to be talking about a gossiping foster carer. Unless I have missed something, your info comes from things birth mum and partner have been posting on facebook. It seems to be that it is out there in public so why you should be castigated for seeing it I am not sure!