In this study, pre-K students were given opportunities to describe their thinking using manipulatives, their own photographs, and other content-related photographs while working to answer assessment questions in the areas of Quantifying, Understanding Spatial Relationships, and Understanding Shapes. Results with manipulatives-only were compared to results with photography. The theoretical framework stemmed from Activity Theory and components of the theory of Realistic Mathematics Education (RME). Ideas from each theory were combined to form a hybrid framework which placed RME at the center of the Activity Theory framework. Key findings from the study show that more students were better able to describe their thinking when referring to photographs than when referring to manipulatives. The mathematical skill with the greatest average number of improved responses with the use of photography was Quantifying, where students were able to give more detailed, more mathematically relevant, and more accurate responses when speaking from photographs as compared to manipulatives. The photography situation with the greatest average number of improved responses was when students were speaking from photographs that were shown to them but that they did not take themselves. For Understanding Spatial Relationships problems and Understanding Shapes problems, students were able to describe more spatial and shape attributes with the use of photography than with the use of manipulatives. Further, students showed fewer distractions with the use of photography in the Understanding Spatial Relationships tasks, and were able to recall more real-world shapes with the use of photography in the Understanding Shapes tasks.