Digital technology, the Internet and mobile communication have made picture taking and sharing ubiquitous. The photograph with its long track record as a representational artefact now portrays individuals in ever broader contexts. The once distinctive practice of the snapshot aesthetic in capturing the banal and everyday has become culturally pervasive and children are key creators, producers and sharers of digital photographs. Designers of innovative digital media for children and young people face real problems in establishing requirements. Early experiments using children's photographs to inspire design and game evaluation methods led to tangible improvements in the user experience. To date however, the benefits of a robust discourse on the vernacular photograph in this context have come secondary to the pragmatics of design. This paper will explore the role of the photograph as a cultural arbitrator in the design of innovative software for personal and social education. It will examine the construct of the photographic index and its changing value in dialogue associated with digital images; will consider how this inherently ambiguous dimension of human experience can be investigated to better appreciate children's affective and cognitive responses to photographs in design contexts and will discuss the benefits and challenges of harnessing the photograph as a cultural arbitrator.