Launched in 2010 as a modest mobile photo-sharing application for Apple’s iPhone that uploads images in a square format and add filters that mimic vintage photographs, Instagram has grown to become one of the most-used social media platforms, alongside Facebook and Twitter. This book examines the rise of Instagram and its impact on visual culture by considering how it has shaped two inter-related and highly popular global forms: graffiti and street art. The book traces the intuitive connections between graffiti, street art and Instagram, beginning with the simple observation that when turned on its side, the scrolling feed of Instagram images displayed on a mobile phone resembles graffiti viewed from the windows of a moving train. It argues that with Instagram’s privileging of flows of images tied to mobile devices and the real-time battles for impact and attention that this generates, is more closely synced with the aesthetics of graffiti and street art and the needs of its producers and consumers than any other digital platforms. It analyses the architecture, data, networks and audiences of Instagram, showing how they underpin a dramatic shift in how graffiti and street art are produced and consumed.