First, the institution of food studies has generally taken a more social, economic, and political perspective on food, rather than attempting a wholesale definition. One of the most quoted definitions comes from Arjun Appadurai, who sees food as a "highly condensed social fact." He points out that when we convert a part of our environment into food, we create a "powerful semiotic device." The boundaries of edibility and palatability often separate cultures, serving as grounds for perceived exoticism, primitiveness, or disgust. So food has a complex material and social DNA.
Second, visual studies sees images as a cultural phenomenon. WJT Mitchell provides a widely cited and coherent definition, understanding images as a family that includes graphic, optical, perceptual, mental, and verbal forms. He also understands images, or pictures, as "worldmaking" devices, rather than world-reflecting devices. The definition I use the most comes from N Katherine Hayles's book on cybernetics and literature. Drawing from information theories, she claims an image is a condensation of information that can be both visually evocative and invite visualization.
The symmetry between her definition of image as a condensation of information and Appadurai's notion of food a highly condensed social fact offers a pathway into defining food images. A food image condenses social information, affording a way of visualizing the world. Although food proper may be a condensed social fact, it does not necessarily lead to visualization or to visually evocative graphics and language. Here, I think, is the boundary between food and food images: it is not edibility that separates them, we can eat food but not food images; rather, it is visualization. When food allows us to visualize, it becomes a food image.
This definition actually accords with Manuel DeLanda's description of Hume's theory of images. Hume didn't think images were reflections of the world. Rather, images, even in the mind, were low-level reproductions of the world. The difference between the actual world and the image of the world was not that one was real and the other was just mental; the difference between world and image was a matter of intensity: the image is a lower-level intensity of the world. A low-level reproduction or image of an apple allows visualization in ways that the material apple cannot. In Proust's famous description of eating a madeleine, he reveals an image of food that allows us to not only represent the actual world but to also produce a world filled with memories, tastes, and psychological drama.
When food allows us to visualize, then it becomes a food image.
