Re: Opt out ?
I don't understand how posting my photo on social media can mean I no longer have copyright over it
You do still have copyright of it - but you no longer have any rights whatsoever as to what it may now be used for. By your own admission you posted an image, therefore you must have signed up to an account - and accepted the T&Cs. You did read the T&Cs didn't you ? No ? Well that's your own fault then.
Typically when you sign up you either assign copyright, or more normally grant the site full rights to do whatever they like with it. That's the bit typically worded along the lines of "you grant ${business} a global licence to use, redistribute, sell, edit, or repurpose the image for any use they want".
This made the TV news a few years ago when someone found their photo being used in an advert in their local bus shelter - turns out they'd not read the T&Cs of a photo sharing website, and the site had licensed the photo to the company doing the advertising. All completely legal - but IIRC the advertiser did remove their photo and use a different one for any new material.
Biting the hand that feeds IT
