The term “sensory image” comes from the German Sinn-Bild, literally “Sense Picture,” and can be translated as symbol, simile or allegory. In his essay “The Origin of the Work of Art” Martin Heidegger says an allegory “makes public something other than itself; it manifests something other.” (145) Its meaning does not lie in what it is an image of, to which we then apply our conceptual understanding; rather meaning is presented through the image to our senses and as such is understood in the immediacy of perception.
Heidegger provides the following definition of the sensory image in the “preliminary considerations” section of The Essence of Truth.
The sensory image “provides a hint or a clue. The image is never intended to stand for itself alone, but indicates that something is to be understood, providing a clue to what this is. The image provides a hint – it leads into the intelligible, into a region of intelligibility (the dimension within which something is understood), into a sense (hence sensory image). However, it is important to bear in mind: what is to be understood is not a sense, but rather an occurence. ‘Sense’ [Sinn] says only: it is a matter of something intelligible. What is understood is never itself sense; we do not understand something as sense, but always ‘in the sense of’. Sense is never the topic of understanding.
The presentation of an allegory, of a sensory image, is therefore nothing else than a clue for seeing (a provision of a clue through which something is presented sensuously). Such a clue leads us to what simple description, be it ever so accurate and rigorous, can never grasp.” (13)