Twitter has become a battleground for election campaigns with almost all political candidates vying for office present on this medium. Studies examining the role of Twitter in election campaigns are numerous but almost exclusively focus on the textual content of tweets. Unexamined so far have been the images contained in those tweets and the messaging they attempt to convey. At the same time, we know that images can have powerful communicative effects that go above and beyond text alone. In this paper, we examine 45,000 campaign images tweeted by candidates during the Irish General Election campaign of 2020. We first present a fine-grained categorisation of those images, including categories such as community engagement, electioneering, image management, and policy content. We then report results from a set of pre-trained and context-specific classifiers used to predict image categories, relying on text and image features. Our results provide novel insight into the manner in which candidates use visual communications alongside text to promote messages to the electorate.