Marx's call for a materialism capable of engaging reality as "sensuous human activity" opens a question about the role of representation in relation to data. Images have increasingly been seen as significant forms of data in the history of education. Derrida's theory of the spectre -- a variation on the positions established in his earlier works on the trace, the supplement and differance -- offers a way of rethinking visual images, their relations with existing discourses of knowledge and with positioned subjects who makes sense. Two early twentieth-century photographs are explored here in relation to ideas derived from Derrida as an exercise in the philosophy of representation.