The concept of image is an irritating and frustrating one: it is absolutely necessary, for we use it all the time; but, at the same time, we can hardly give it a definition. ‘Image’ belongs to those kinds of terms everybody immediately understands as long as they are not strictly defined, but immediately disagrees with once they are given a definition. In other words, a broad notion of image is accepted precisely because it is broad. But a definition of image valid in one field will not easily be accepted in another field, precisely because it is too narrow. To give an example, in his introduction to an important book for this topic, Images and Understanding, Horace Barlow proposed to classify people interested in images into two groups: ‘those who are mainly concerned with images in the outside world before they are presented to the eye, and those [like Barlow himself] who investigate what happens to them after they have entered the eye’. As an art historian, I belong to the first group. However, as many artists since Seurat have included in their work subjective phenomena of visual perception, I also need to have a foot in the second group. Furthermore, I will argue that it is hardly possible to isolate a purely visual image from the other interrelated aspects of images. © 2005 Taylor & Francis Group, LLC.