'The link to Who is watching you?' vanished!
In brief, photos taken with a mobile (cell) phone can be used in much the same way as GPS to track the person or persons portrayed. This is particularly worrying where children are concerned as they may be traced to their homes, schools, favourite haunts without their or their parents' knowledge and you may be sure that anyone stalking children in this way is up to no good.
There are settings on mobile phones that will deactivate the tracking capability but, as with most technology, mischievous people can and will hack into them.
It is frightening to realise how truly vulnerable we are. We guard our keys, wallets and other personal possessions so carefully but unwittingly expose those we love to danger simply by recording them and making those photographs public.
Photos taken with ordinary cameras are not traceable.