The creation of meaning in texts requires the use not only of the verbal but also of the visual way, while understanding the text needs to understand the messages expressed verbally and visually, such as photographs, diagrams, charts, maps, sketches play a significant role.
Kalantzis, M. & Cope, B. (2001) Πολυγραμματισμοί (Multiliteracies)
Kress and van Leeuwen have noted that visual communication is becoming so critical in the field of public communication, that inevitably attracts visual literacy is not just social approval, but is now a matter of survival. To learn to understand texts essentially means learning to "read" verbal and visual messages.