You might be on holiday, but it is also possible a hacker has got hold of your password, so Facebook's social authentication system blocks these logins unless you can
identify photos of your friends.
Not exact matches
Once Riya knows what you look like, you'll be able to find yourself in
photos uploaded by your
friends or
identify strangers in pictures
of your own.
Mine
identifies «people» in my
photo album, including an individual I would not have thought
of putting on my
friends list, although other sheep may find it charming.
Most daters either post
photos with a group
of friends (so you can't really
identify the person you are meeting), or they post
photos of their cats or random objects.
That would be a boon for Facebook's People You May Know tool, allowing it to suggest as
friends people whose faces appeared in the background
of photos it
identified you in, or vice versa.