true, as far as perception is concerned, writing and pictures, for instance, do not call upon the same type of consciousness; and even with pictures, one can use many kinds of reading: a diagram lends itself to signification more than a drawing, a copy more than an original, and a caricature more than a portrait. but this is the point: we are no longer dealing here with a theoretical mode of representation: we are dealing with this particular image, which is given for this particular signification.

roland barthes, mythologies (1957)