This paper aligns with a field of research that deals with the use of multimodal metaphors from a cognitive-discursive perspective. In this context, we aim to investigate the role played by images in the instantiation of cross-domain mappings in a particular genre. Specifically, we describe and analyze the cognitive-discursive nature and functioning of visual metaphors in political and social cartoons. This paper first explores the concepts of image schemas, image metaphors, and visual metaphors, as well as the notion of metaphoricity in discourse. We then carry out the analysis of multimodal metaphors in a corpus of editorial cartoons that depict the Covid-19 pandemic, and other related issues within social and political contexts. Some of our findings suggest that cartoons often evoke multilayered off-line frames, image metaphors and conceptual metaphors in order to enhance the persuasive power of their semiotic arrangement, especially by inviting their audience to actively participate in meaning-construction processes