Visual images played an increasing role in professional discourse and in popular and political debate about progressive education over a century or more. In the early 1900s photography was adopted by some progressive texts to convey new ideas illustrated by practice. This paper highlights an iconic example: John and Evelyn Dewey's celebrated "Schools of To-Morrow" (1915), with reference to a small selection of its photographic illustrations. Consideration is given to how images were constructed, their status as historical evidence and issues of interpretation. Comparison is made with other illustrated works, preceding and following Schools of "To-Morrow", by advocates of child- or student-centred pedagogies. The article urges critical reflection on visual representation in arguments for and against progressivism in more recent times. Insights drawn from earlier examples should be borne in mind by historians seeking to evaluate the role of pictorial sources in discourses of pedagogical reform.