In the book ‘regarding the pain of others’, why does Sontag juxtapose the different representations of suffering, such as photographs and literature ?

Sontag argues that reality cannot be fully articulated via film. Even though photographs are widely considered objectively true,—true enough even for a court of law—Sontag contends that a photograph is nevertheless open to manipulation, misrepresentation and interpretation. The meaning of a photograph is not based upon objective truth, but rather on the viewer's engagement with the photo.

Objectively, explains Sontag, a photograph is a discrete unit of a larger unknowable whole. The viewer cannot see what lay outside the frame. Nor can the viewer tell what happened just before the image was taken. The subject, for all that the viewer knows, may have been tampered with. The photo's caption may claim that it shows something other than what it actually shows. Either the viewer accepts what the photo claims or seems to be, or the viewer assigns his or own subjective meaning to the image. In either case, the truth is far from certain.