With multimodal methods and material gaining traction in classrooms, the need to critically assess these becomes increasingly important, especially in order to verify their efficacy and ability to meet the needs of each individual student, regardless of ability or special requirements. In the case of this study, the focus is on textbooks produced for the course Historia 1b at the upper secondary level of the Swedish education system. By analyzing the readability, layout, and functions of illustrations in three textbooks, as well as the gender representation in the material, the aim of this study is to generate a quantifiable dataset, on which conclusions regarding the efficacy of said illustrations can be made. Additionally, the results of this study are compared to those of previous studies, to ascertain whether there is a quantifiable difference in the use of illustrations in textbooks published for use in different curricula.  The results of this study indicate that there is a marginal improvement in the use of illustrations between textbooks produced for the current and the previous curriculum. Additionally, the data suggests that the representation of women in illustrations in textbooks has increased in comparison to previous studies. However, the findings indicate that there is still a need for further improvements regarding the use of illustrations in textbooks, as well as more thorough evaluations of the possibility of diminishing returns in the case of their readability.