Conceptualizations of teacher knowledge have shifted to focusing on the role of experiential rather than theoretical knowledge. There are different approaches to this, but the idea of an image that guides practice is widespread. One approach to images that has not been frequently investigated in studies of second language teachers is through sociocultural theory, specifically in the contribution of activity theory known as "orienting activity". In this view, images mediate teaching actions by linking theoretical knowledge and practical experience. This article will use orienting activity to examine the role that images play in an English as a second language teacher's personal practical knowledge by drawing on classroom observations, informal discussions, simulated recall interviews and documentary evidence collected over a nine month period. Analysis of the data shows that several key images mediated the teacher's classroom actions. These emerged in the observations and in the teacher's commentary on planned and spontaneous, routine and novel and successful and unsuccessful activities. The images appeared to have developed through both tacit knowledge associated with practical experience and theoretical knowledge associated with research and theory. This demonstrates the usefulness of orienting activity as a theoretical framework for exploring classroom practices and teacher development through the links it can make between theory and practice.