Pink, S. (2004). Visual research. In M. S. Lewis-Beck, A. Bryman, & T. F. Liao (Eds.), The SAGE encyclopedia of social science research methods (pp. 1186). Thousand Oaks, CA: Sage. (Republished in 2011 in SAGE research methods, doi: 10.4135/9781412950589).
Sara Pink provides a very brief introduction to the history and contemporary uses of visual research, with an emphasis on ethnographic applications. She situates visual research within a social science context and social science methods more broadly.