Ben's photo was a framed photograph that Benjamin Linus kept of his adoptive daughter Alex near his desk, even when he traveled. ("Through the Looking Glass, Part 1") The continuity of the same prop has been maintained through at least three episodes: "One of Us", "The Brig", and "Through the Looking Glass, Part 1".
A duplicate of the photograph in a different frame sat on a shelf in Ben's house, both before and after the Others' abandonment of the Barracks. ("Meet Kevin Johnson")
The same photo in a different frame sits on a shelf at Ben's house in the Barracks
. ("One of Us")
A number of other photos of what is presumably the same girl adorn the walls of Ben's house. ("Meet Kevin Johnson")