The systemic functional (SF) approach to multimodal discourse analysis (MDA) is concerned with the theory and practice of analysing meaning arising from the use of multiple semiotic resources in discourses which range from written, printed and electronic texts to material lived-in reality. The SF-MDA approach developed in this article explores the meaning arising through the use of language and visual imagery in printed texts. This involves investigation of linguistic and visual forms of semiosis, and formulation of cross-functional systems such as colour. An integrative platform based on the SF metafunctional principle is proposed, and intersemiotic mechanisms and systems (content and expression strata) are developed to capture the expansion of meaning which occurs when linguistic and visual forms combine. The SF-MDA approach is demonstrated through the analysis of ideational meaning in a print advertisement. The practical approach involves the use of digital technology in the form of image-editing software which gives rise to a more detailed semantic and ideological interpretation. The analysis reveals how metaphorical constructions of meaning (i.e. semiotic metaphors) take place across linguistic and visual elements.