See https://developers.facebook.com/docs/reference/fql/photo_tag/
To get links you have to run query like
select link from photo where object_id in
(select object_id from photo_tag where subject=me())
Of courset instead of me()
you have to write your friend id.
Note, that
To read the photo_tag table you need the following permissions: User: user_photos permissions to access photo tag information that a user is tagged in. friends_photos permissions to access photo tag information that a friend is tagged in.
BTW you will receive photos on which the person is tagged, but these photos may contain no real image of person.