The research reported on here elaborated on the effects that images displayed on the walls have in schools as a variable in evaluating the educational quality. Mixed methods were used to analyse the images displayed on the walls of 27 classrooms to determine their provenance and authorship. The results show quantitative, qualitative and aesthetical values of the school visual culture, thanks to the numerous photographic series (resembling in graphs) which are a testimony of each classroom. After the typologies of the displayed images at the schools had been documented, it was demonstrated that images mostly come from the school products industry and from faculty members. The kind of analysis and the conclusions that were obtained could be considered in other contexts of schools with cultural diversity. Four alternatives are proposed in order to improve schools' visual culture diversity: (1) consensus between the entire educative community -- both adults and children selecting which images should adorn the classroom walls; (2) an increasing of external images, but generated by students and teachers about their personal experiences to increase the sense of belonging in the classroom; (3) a greater presence of internal images created by specialised agents, that enrich the learning processes, diversity, iconography and style of the images; and (4) the emphasis of elementary teachers' visual education to integrate images pedagogically.