Academic analysis of the growth and nature of political campaigning online has concentrated largely on textual interactions between politicians, parties, their members, and supporters, as well as voters more widely. In evaluating the shift from traditional to online campaigning techniques, the use of social media’s increasingly visual capabilities has been comparatively neglected in research. This article considers one type of online visual political communication, the online political poster, in terms of its strategic campaign functions relating to persuasive and organizational roles. The article uses a case study of an extensive data set of online political posters collected from political parties in the United Kingdom, on Facebook, between September 2013 through to and including the general election in May 2015, to try to understand how parties used online political posters and how audiences responded to them. The findings show that despite a clear emphasis on sharing images, very few received widespread attention, arguably limiting their persuasive role. However, their prevalence suggests a role relating to parties trying to maintain relationships with existing online supporters as a form of displaying virtual presence, credibility, and belonging, paralleling the function of traditional window posters and yard signs but in a social media setting.