Companies have frequently used visuals (e.g., still images and videos) as part of their corporate social responsibility (CSR) communication strategies, and those visuals often contain emotional content. As yet, however, scholars and practitioners have little understanding of how emotional design influences the effectiveness of CSR communication. This study examined how the emotional valence and arousal generated from contextual images in CSR messages affected the perceived CSR motives of companies, attitude toward the companies, purchase intention, and CSR participation intention. The results of a 2 (valence: positive vs. negative) × 2 (arousal: calm vs. arousing) experiment showed that arousing negative images elicited the highest level of attributing public-serving CSR motives to companies, the most favorable attitude toward the companies, and the strongest purchase intention, and CSR participation intention. We discuss the theoretical and practical implications.