does anyone know how to make sure your nudes aren't online

I've always wanted to start a YouTube channel. not for fame but to connect with people who struggle with the things I do. I've had an ex who turned on my and threatened to show my nudes to everyone( and before you say it, yes ik you shouldn't send nudes. yes, ik it was stupid. yes, ik I was an idiot who can't unsend them) as far as ik he never posted them anywhere. (i haven't sent any new bfs pics since) but how to i make sure no one can dig them up?