Up until now, the study of the argumentative role of visuals has been restricted to the formal concept of argument as product, consisting of premises and conclusion. In this paper, I adopt the pragma-dialectical approach to argumentation as a social and discursive activity in order to explore argumentative functions of visuals that go beyond claiming and justifying. To do this I pay attention to the visual form and to the interaction between the verbal and the visual mode in argumentative discourse.