The pedagogical potential of conversational and communicative images has not been fully recognized and is rarely a part of teachers training programs. In this article, the authors outline a semiotic approach to teaching. In this specific case, the approach is based on developing pedagogical tools that allow for the reasoned use of current media and practices’ inherent multimodality. Images constitute a powerful tool for the differentiated anchoring of knowledge, thanks to their affective dimension. Whether digital or analog, images know no disciplinary boundaries and support oral, written, reflexive and creative activities. A multimodal practice by definition, the use of images in the classroom as a means of mediating knowledge implies taking into account their opposition to speech: the spatiality and polysemy of images are confronted with the linearity and monosemy to which the latter tends. It is thus a complex semiosis, in which Gunther Kress sees a highly reflexive and creative metaphorical process (Kress, 2010). “Image as a medium for pedagogical discourse”, a master level interdisciplinary seminar offered at the Haute Ecole Pédagogique in Lausanne, is the subject of this contribution. By questioning the impact of images on pedagogical discourse, this course seeks to provide future teachers with the following: an understanding of the mechanisms of the image-discourse relationship; an comprehension of the pedagogical applications of spatial and symbolic thinking; a basic mastering of visual language; and the ability to take into account the subjectivity of reception. Dismiss the verb is a futile operation. Thus, in light of current socio-cultural practices, we have chosen to take a decentralized approach. Iconotextual communication is omnipresent. It is therefore important to recognize its capacity to mobilize modalities in their respective sign systems, as well as the unique message generated by combining text and image.