How does a photograph guarantee anonymity?

Admittedly, it's an old photograph of a then-child, but individuals do not alter so dramatically that she would be unidentifiable.

"The injunction prevents the publication of their new names or addresses for the rest of their lives.

Shannon was the victim of a hoax kidnapping in 2008 staged by her mother Karen Matthews and Michael Donovan in a bid to claim a £50,000 reward.

The order was granted to protect Shannon and her siblings from any harm identifying them may cause."
https://www.bbc.com/news/uk-england-leeds-54011377