This paper focuses on the use of stand alone visuals as a health promotion medium in South-Africa. First, it surveys the effectiveness of visuals as health intervention medium in a low literacy context. Second, it presents an interpretation framework for complex communicative visuals, based on two related ideas: (i) the interpretation of visuals benefits from different types of natural correspondences with perceptual real world experiences, and (ii) interpreting visuals requires three interpretation strategies (symptomatic, iconic, symbolic) which increase in the level of abstraction they require and decrease in the level of natural correspondence with the real world they rely on. This framework enables to predict an increase in comprehension problems as visuals rely less on natural correspondences and require more abstract interpretation strategies. Furthermore, these comprehension problems are expected to increase as viewers are less experienced and educated in reading the formal language of visuals. Third, it presents the set up and results of a study in which these predictions are tested. The study asked literate and low literate South African respondents to interpret complex visuals taken from recent South African HIV/AIDS brochures. The results confirm a decrease in comprehension performance as visuals require more abstract, convention based interpretation strategies, an evolution which is more pronounced in the group of low literates.