The proliferation of computation in our everyday environment enables new types of interaction and communication devices. Understanding the dialogue between users and such technology is crucial to the success of future urban computing deployments. We investigate human behaviour in public spaces using a public photography service deployed on interactive public displays in an urban city. Through the analysis of user-generated snapshots we show that the service was rapidly appropriated outside its intended purpose, resulting in use that differs substantially from those previously documented in photography literature. We reflect on the reasons why the service was appropriated in this way and explore the evolution of photography in urban contexts. Ultimately, our findings help ground our understanding of human behaviour in urban spaces and thus contribute to the design of future Ubicomp deployments. © 2015 ACM.