This case study explores the use of photo elicitation methodology and children's photography as a method of researching children's early mathematical experiences and understandings. In the years 2008-2010, I undertook a PhD study which explored the experiences children have with, and understandings of, mathematics (specifically, measurement) as they transition to primary school. The study focused on the experiences children have in prior-to-school and out-of-school settings and how these experiences contribute to their measurement development. Children shared their experiences and understandings through drawings, photographs, and narratives which accompanied these visual representations. In this case study, I focus on the use of children's photography as a research method to elicit children's experiences and understandings. The case shares both the strengths and challenges of using this method, giving examples from the PhD study. Although the PhD study focused on mathematics specifically, children's photography is a method which could be utilized to explore children's lives and learning more generally. As such, this case study presents a general discussion of photography as a method for researching with children, taking into account both the methodological and ethical considerations associated with this approach. [This content is provided in the format of an e-book.]