The role of traditional media (television and magazines) in creating eating disorder risk has long been a topic of discussion and research, but the proliferation of social media and rapid increase in the use of the Internet by adolescents generates new dynamics and new risks for the development and maintenance of eating disorders. Recent research describes the relationship between Internet and social media use and eating disorders risk, with the greatest associations found among youth with high levels of engagement and investment in photo-based activities and platforms. Here, we review different types of online content and how they are relevant to eating disorders and consider the theoretical frameworks predicting relationships between Internet and social media and eating disorders, before examining the empirical evidence for the risks posed by the online content in the development and maintenance of eating disorders. We describe proeating disorder content specifically and examine the research related to it; we then consider the implications of such content, highlight directions for future research, and discuss possible prevention and intervention strategies.