George L Dillion's text Writing with Images: Towards a semiotics of the Web starts with the pictorial turn. In the Introduction he says:

Scholars and critics have begun writing accounts of this "pictorial turn," "turn to the visual," or "foregrounding of the visual." These accounts cluster in two groups: stories of a Fall or falling out between words and images leading to the subordination of images to texts and closely related stories about the rise (or restoration) of images to the role of a new international medium or, alternatively, to the emergence of a new integration of imagetext or visual language.

Dillion says that:

One version of the Fall is W. J. T. Mitchell's, which starts from a notion of imagetext as a level of meaning which is not medium specific, in which word and image mutually complement and reinforce each other (not necessarily by "saying the same thing"). Mitchell disputes the Modernist notion that each medium has its own unique mode of operation and is best pursued by avoiding doing the work appropriate to another medium. This radical separation of media, Mitchell argues, may have the effect of protecting the visual arts from being annexed to talk and to verbal accounts of visual meaning, but it is not easy to find pure types anywhere in history nor is it exactly clear how we can talk about writing without involving the visual. There are no pure media, Mitchell argues, in the sense that Clement Greenberg among others assumed. So Modernism is the Fall for Mitchell, with its tendency to look down on Blake's illustrated books on the high art side and Trudeau's Doonesbury on the side of more popular culture. Mitchell identifies a major theme of post Modern art, especially visual art: how and in what interesting ways can the two signifying systems be set in motion within a single work?