Visual representations are ubiquitous in modern-day science textbooks and have in recent years become an object of criticism and scrutiny. This article examines the extent to which changes in representations in textbooks published in the USA over the past six decades have invited those critiques. Drawing from a correlational analysis of a corpus of 34 US middle school physical science textbooks, continuities are established with respect to the purposes that most textbook images serve and the numbers of schematic representations that are used. Changes are observed in the overall total number of representations in textbooks and in the proportion of representations that are photographic. Interpretive cases of individual representations over time are presented to further illustrate the continuities and changes that have taken place. Specifically, high-fidelity images, such as photographs, are shown permeating or replacing schematic and explanatory images in the interest of promoting familiarization to students. This shifting emphasis toward familiarization is discussed as a specific cause for concern about quality and utility of representations in modern-day US science textbooks. (Contains 2 notes and 10 figures.)