Examines how students interacted with a computer-based feature in Urinalysis Tutor(TM), "Compare and Contrast," which facilitated image comparisons. Three main image-viewing modes emerged. Overall, anchored viewing was the predominant image-viewing mode. Results suggest that a computer instructional program with a user-controlled interactivity feature can provide insights on how learners form different types of visual comparison strategies. (Contains 22 references.) (AEF)