This paper considers ways in which photographs help our understanding and teaching of mathematics. Some historical landmarks are considered from Muybridges galloping horses to mathematics trails snapped with mobile phones. The possibilities have always been limited by the available technology and have been shaped by changing attitudes to mathematics teaching. It is argued that in mathematics teaching, photographs are not just for illustration. They provoke discussion, pose problems and provide data. We can measure them and model them with graphs. The approach adopted for developing the Problem Pictures calendars and CD-ROMs is described together with some of the ways these resources are used.