Wikipedia defines visual literacy as;

Visual literacy is the set of skills involved in the interpretation and criticism of images. The concept of visual literacy is also the ability to create and use images to communicate. Visual literacy is a field of study in academia, drawing on art history and criticism, psychology, semiotics, philosophy, information design and graphic design. It is also a goal of education paralleling linguistic literacy. The basic skills of visual literacy include the vocabulary of concepts necessary for understanding and discussing images and visual symbols. Visual literacy can also include rhetorical analysis of the ways different media convey their arguments or messages visually.”