Albert Einstein described the motives for scientific study as a need to construct a satisfactory image of the world: "Man seeks to form for himself, in whatever manner is suitable for him, a simplified and lucid image of our world, and so to overcome the world of experience by striving to replace it to some extent by this image. This is what the painter does, and the poet, the speculative philosopher, the natural scientist, each in his own way. Into this image and its formation he places the center of gravity of his emotional life, in order to attain the peace and serenity he cannot find within the narrow confines of swirling personal experience." (Quoted in Steven J. Heims, The Cybernetic Group.)
"Anything about which one knows that one soon will not have it around becomes an image." Walter Benjamin (Charles Baudelaire: A lyric poet in the era of high capitalism.)
As W.J.T. Mitchell points out, a wide variety of things go by the name of images: pictures, statues, optical illusions, maps, diagrams, dreams, hallucinations, spectacles, projections, poems, patterns, memories, and even ideas. (Iconolgy, p.9) He proposes to treat the variety of images as a kind of "family tree" in which images have differentiated themselves from on another on the basis of boundaries between institutional discourses.
The status of mental representation in general, and the mental image in particular, has been one of the main battlegrounds of modern theories of the mind. A mental image (one of the senses of the German Vorstellung , also translated as " representation") of an object in external reality is an inner, subjective semblance of the external object. Other figures for this relationship, developed through Aristotle, Hobbes, Locke, and Hume, are a mirror, a map, a camera obscura , or a surface for drawing or painting.
Of course, images are not only internal. The other German word for image is Bild . Adlof Hildebrand described the visual processes by which we develop concepts of form out of changing appearance. Hildebrand used the way an artist steps back from his work to take it all in at once as the model of a complete image. (Fernbild )
W.J.T. Mitchell describes the image as requiring a paradoxical trick of consciousness, an ability to see something as "there" and "not there" at the same time. (Iconolgy, p.17) In the famous story of Zeuxis' skill as a painter, he deceived sparrows into pecking at painted grapes. They saw real grapes, not images. But if I point to the image to someone who doesn't already know what an image is and say, "There, that is an image." The reply may be, "Do you mean that colored surface?" Or, "Do you mean those grapes?"
For Henri Bergson, matter is an aggregate of "images," by which he means "a certain existence that is more that that which the idealist calls a representation, but less than that which the realist calls a thing -- an existence placed halfway between the "thing" and the "representation." (Matter and Memory, preface, p.9) Bergson seeks to consider matter before that disassociation which idealism and realism have brought between the existence of matter and its appearance. He appeals to a pre-philosophical "common sense" that believes that matter exists just as it is perceived -- as an image.
According to Bergson, the critical work of Kant, which limited the range and value of our senses and understanding, would have been unnecessary, if the positions of both Descartes and Berkeley had not been taken seriously. "Descartes, no doubt, had put matter too far from us when he made it one with geometrical extensity. But in order to bring it nearer to us, there was no need to go to the point of making it one with our own mind." (p.11)
For Bergson, the body is a special image, which persists in the midst of the others, and constitutes at every moment, a transversal section of the universal becoming. (Matter and Memory, p.151) "It is then the place of passage of the movements received and thrown back, a hyphen , a connecting link between the things which act upon me and the things upon which I act." (see Bergson's distinction between habit and memory)
For Adolf Göller, the process of formation of "memory images" is the source of the pleasure we take in pure forms (that are independent of conceptual or symbolic meaning)
For Freud, images can carry an affective or mnemic charge.
Brian Massumi describes an image as "the translation of a dynamism from one level of reality to another of different dimensionality." (p185) -- a contraction or dilation of dimension.