This introduction sets the basis for the contributions in the volume by developing a concept of “image testimony”, which has yet to be fully theorized. It traces how visuality and vision, image and imaging technology have shaped theories of witnessing from early on. Given the accelerated visual economy in the social web today, a new approach to theorizing image testimony has become necessary. In relation to contemporary image practices, the authors highlight the plurality of witnessing as well as the affectivity of image testimonies in order to shape a new approach to testimony theory. By bringing together diverse disciplinary perspectives and the case studies discussed throughout the volume, the introduction provides a comprehensive overview of the core arguments, thus giving way to a multifaceted understanding of image testimony as an emerging field of study.