Second check to see if the photographs are taken from different angles. Close to 90 degrees is best.
Good example: You are measuring the front of a historic building, and you have three photographs- one taken straight on, one from the left corner and one from the right corner.
Bad example: You have a bunch of photographs of an accident scene and all the shots have been taken by the person walking down the center line of the road so the angle between the shots is almost zero degrees.