Images are commonly used in environmental advocacy campaigns that are designed to promote collective action. However, the effects of different types of images have rarely been examined. In three experiments (combined N = 1426), we tested the impact of commonly used campaign images (meeting, protest, or no image) on willingness to engage in collective action against coal mining. Further, we examined whether images influence known drivers of collective action. Results support the Social Identity Model of Collective Action in environmental contexts: efficacy, identification and anger were strongly associated with collective action intentions and (less so) behaviour. Identification was the strongest predictor of actual behaviour. The effects of images were inconsistent. Image presence and type sometimes affected collective action responses, either directly or indirectly. The presence of an image sometimes increased perceptions of descriptive norms for action, which in turn increased perceived efficacy and collective action intentions.