The implementation of Curriclulum in Greek primary school coheres with the transition from everyday language to the taxonomic language of science, which organizes and reforms the common experience of students. This transition is noticeable through the texts of schoolbooks as "semiotic recourses" for the recontextualization of knowledge beeing produced at school. On the other hand, the wide use of pictures in school textbooks indicates a significant turn of semiotic recources and literacy theories to multimodality, which is incorporated in education according to the authors' methodological approaches. Based on the theory of Social Semiotics about multimodality in education, which is used in accordance with Systemic Functional Linguistics, an effort is made in this paper to analyse the images of 6th grade primary school textbooks of Science. The aim of this analysis is to reveal the functional role of the pictures for students' school and science literacy, according to the agency of the authors to provide modern and comprehensive textbooks.