PurposeThis paper explores the communication of legitimacy in the annual reports of non-governmental organizations (NGOs), focusing specifically on the function of images. The visual mode of discourse and meaning construction has to date only scarcely been explored in legitimacy research, especially in the NGO context.Design/methodology/approachDistinguishing between normative, regulatory, cognitive and outcome legitimacy, the paper inquires into the kinds of legitimacy that NGOs communicate to their constituents and the claims that predominate. Turning to research on impression management, the paper explores whether and how organizations use images as symbolic mechanisms of legitimacy. Finally, the paper considers the socio-cultural implications of these legitimation strategies for beneficiary groups, donor communities and the organizations themselves.FindingsA qualitative content analysis of images in the reports of the eight influential members of the US-based Global Emergency Response Coalition confirms the widespread presence of legitimacy claims in NGO visual communications, with normative (especially need) and output (especially implementation) categories predominating. However, these practices are potentially contradictory; measures to increase legitimacy to and of donors result in forms of beneficiary exclusion and reduction. Strategies of impression management, namely self-promotion, ingratiation and exemplification, appear to shape these NGO representative logics.Originality/valueThe results of this study extend prior research into legitimacy, legitimation and impression management in and beyond the non-governmental sector by differentiating among categories of legitimacy and incorporating images as the object of analysis. In this capacity, they also support and augment the emerging literature on imagery use in NGO annual reports.