We designed and iterated on a photo browsing application for high-end mobile phones. The application, Zurfer, supports viewing of photos from the user, their contacts, and the general user population. Photos are organized using a channel metaphor, driven by multiple dimensions: social, spatial and topical. Zurfer was deployed to over 500 users; extensive user research was conducted with nine participants. The data from the deployment and the study exposes general themes of mobile application use, as well as requirements for mobile applications in the photos domain, mobile social applications, and entertainmentdriven mobile applications. Author Keywords Mobile, photographs, mobile applications, user study, photo sharing, photo browsing. ACM Classification Keywords H5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous.