In this article, we study the role of teacher support in a collaborative learning setting that involves students' constructions of visual representations in the environmental education context. Despite the consensus in the field of science education research that engagement with visual representations--such as diagrams, animations, and graphs--can support students' conceptual understanding, studies reveal that learning from engagement with visual representations can be challenging for students. Adopting a sociocultural approach, this study contributes to extant research by analytically scrutinizing the role of teacher support in learning activities that revolve around students' construction of visual representations. The empirical basis is a science project in which lower secondary school students drew and refined depictions of the effects of anthropogenic climate change. The analytical focus is on student-teacher interactions during group-based drawing activities in which students created representations of the carbon cycle and interacted with authorized representations. The analyses revealed how students found it challenging to compare, contrast, and integrate authorized representations and, additionally, to constructively use authorized representations in the process of designing their own representations. To support students in their efforts to construct scientific meaning, the teacher oriented the students' attention towards the salient features of representations, supported students in making sense of 'semiotic signs', and enabled them to link scientific concepts with detailed depictions. In addition to the different forms of support provided by the teacher, the analyses of the student-teacher interactions also reveal the teacher's use of specific 'talk moves' of elaboration and eliciting. The key implications include that teachers should select representations that are sufficiently different in terms of how concepts and phenomena are depicted, and that teachers should be prepared to support students in how to compare and contrast multiple representations. Further, strategies for supporting students' exploration of their own ideas and suggestions are essential in the dynamics between students' self-made representations and authorized representations.