The photographs taken before treatment starts are part of the analysis of the soft tissues of the face: how prominent the lips are, the position of the nose and chin in profile, the symmetry of the face and chin, the position of the dental midline, how much of the teeth shows when you smile and how they relate to the lips. Once orthodontic treatment is complete, we take the same set of photographs at the end. At this stage, together with the impression, they serve as a record of exactly how the teeth were aligned when the braces (or aligners) were removed.
This answer is for general information. Your own case needs an examination by an orthodontist.