Mum won't accept I don't want someone seeing my child so now I've said my mum can't either.

YANBU, but you need to stop using your mum for childcare.

I want to second the advice to report them to the police.

I think it might qualify as harassment.

Even if they don't do anything, the incident will be on record and you'll have a crime number and can refer to the incident if they ever try to pull a similar stunt again. It's much easier to get a police report than a SS case to refer to down the road. A police report is the first step on the path to a restraining order too, should you ever need one.

Your child will go to nursery and then to school and they could easily call a nursery or a school to report negligence, abuse, accuse you of prostitution in the home, drug taking, drink driving with DS, etc.

What was the original falling out over? It seems like an absolutely mental thing to do because of a falling out, has she done other things like this? You should absolutely keep your child away from them and try not to feel bad about it

You are not being unreasonable OP. Your post resonates with me as I have a challenging sibling. I would be adamant about this.

I'd keep away from all of them. Your brother and SIL sound vile. Your mother clearly will not respect your requests to keep them away from your child . You have done nothing wrong here. Your child will be better off without them . Done feel guilty about anything!!! Your mother should respect your requests and this would not escalate

No good deed goes unpunished, eh...

Your mum has something seriously qrong wirh her if she expects you to just shrug about what SIL did.

I would actually not trust SIL around your child at all. She has no moral compass.

You are completely justified in cooling things with your mum.

I don't know if the police will "act" but its a process isn't it, like with harassment of any kind, you build up a report history of it happening as evidence for use / protection further down the line if and when the harassing behaviors escalate.

Stand your ground. Your mother sounds as horrible as the others.

Also, surely it's illegal? Defamation, no? The police should be looking into them because it is not normal at all.

Creating fake photos to shop you to social services isn't just a family row, it's a serious attack. If your mum can't see that and keep your child away from the perps, she'll have to stop looking after him. What a shame for both of you.

I agree with @AngelicKaty that you should go to the police and have SS back you up.

I am really shocked this happened and I'm so sorry that it did. I think that you're vulnerable and they have not only been taking advantage of you, they are trying to actively hurt you and damage your mental health.

Not sure if this is possible, but you might consider getting a restraining order on all of them, based on previous behaviors.

Can you get advice and support from the SS?

Jeez. This.
stay well away from all of them.

That’s horrific behaviour from them. Imagine going as far as doctoring child abuse images ffs

Well done for taking control and protecting you and your child. Your mum will eventually fall out with those nasty fuckers.

YANBU. What they did was truly appalling OP - such premeditated maliciousness on their part could have had devastating consequences for you and your DC - it's simply unforgiveable and your decision to stop your "D"M having your DC is absolutely the right response.
Re. them suffering no consequences for their actions, you could make a complaint to the police as you have evidence from Social Services confirming that the photo's were doctored and what they did could be covered by the Malicious Communications Act 1988, particularly since they did it "with the intention to cause distress or harm". The Act makes it a crime to send a communication that is indecent or grossly offensive, a threat, or conveys information that is false and known or believed to be false by the sender, where the purpose is to cause distress or anxiety. Even if it comes to nothing OP, it would put the wind up them when the police contact them - see how they like it!

Why on earth would your brother and sister in law do that? It's horrible.

YANBU @RachCmomma, not in the slightest. All of them sound absolutely vile. There should be a legal route to deal with these people who make totally malicious complaints out of spite.

I’d feel exactly the same.

I'd go NC with both. No way should you put up with that

They all sound awful. You're well rid.

I would change all the locks in your house OP, these people are dangerous I wouldn't trust them not to have had copies of keys made when they had access to your home.

Don’t feel bad, you are not the villain here.
Well done on setting boundaries with your mother and you are doing the right thing by not allowing her to see your child on her own as you obviously cannot trust her.