The influence of the number of pictures in college textbooks on students' understanding of the text was studied. For six history texts, the numbers of pages, maps, and pictures were compared. Charts, graphs, and diagrams of processes were not counted. While the number of pages and the number of maps in these books have not changed significantly, the number of pictures has increased. To determine whether pictures improve students' reading comprehension, a 1,108-word passage was illustrated with three pictures. Following reading of the passage, students completed 15 multiple-choice comprehensive questions that tested both literal and implied meanings, as well as a vocabulary test. For 140 students in eight classes, half the classes were tested with the pictures and half without pictures. No significant differences in the performance of the two groups occurred. In a second study with 145 students, 119 chose a handout with a reading passage illustrated with pictures, while only 26 chose a passage without pictures. It is concluded that while there seems to be no cognitive benefit for increasing the use of pictures, they seem to have an affective impact on students. (SW)