He is a good detective because he has a 'photographic memory'.
I reduced the images 'photographically'.
the 'photographic' process
(..) I haven't even been born yet. And look at this picture. It's my brother, my sister and me. Look at her sweatshirt, Doc. Class of ? DOC: Pretty mediocre photographic fakery. They cut off your brother's hair. I'm telling the truth. You got to believe me. Then tell me, future boy... (..)1985 Back to the Future