Do images mean anything?

We analyze the operations that form the conceptual foundation of a traditional database: the determination and matching of the meaning of a record of data. With a careful definition of the "meaning" of a piece of data, we show that matching can be naturally defined. We then analyze whether a similar concept can be applied to image databases. We argue that several concepts, that led to image database models based on matching, cannot be reasonably extended to the visual world of a perceptual search engine.