Picture books discussed with pupils in primary school are considered multimodal texts, as they combine at least two communication codes (verbal and visual). A discussion involving picture books will normally be included in Slovenian language lessons, with pupils focussing mostly on the text. The visual aspect, which equally carries a message, is often neglected. The objective of the present case study that was conducted among fifth-grade primary school pupils in the 2018/19 school year was to explore how a cross-curricular approach to planning and executing the lessons in the Slovenian language and visual art can help pupils learn about the characteristics of the picture book as a multimodal text. We conducted a set of didactic activities entitled Getting to know the picture book, introducing selected picture books to pupils as part of their Slovenian language classes, which resulted in them developing their receptive skills while observing and defining the structure of the texts. In visual art classes, the pupils learned about the visual features of the picture book. As a productive response to the picture book discussed, the pupils were instructed to complete the following tasks: design a cover for their own picture book, design endpapers, illustrate their own poem, and produce their own leporello. The survey involved 21 pupils, a generalist teacher, and a researcher in art didactics. The case study was completed in five weeks. The data were obtained by means of initial and final testing, questionnaires for pupils, and participant observation.