The painting shows a pipe. Below it, Magritte painted, Ceci n'est pas une pipe., French for "This is not a pipe."

His statement is taken to mean that the painting itself is not a pipe. The painting is merely an image of a pipe. Hence, the description, "this is not a pipe."

Similarly, the image shown above is neither a pipe nor even a painting, but rather a digital photograph.

The painting is sometimes given as an example of meta message conveyed by paralanguage. Compare with Korzybski's The word is not the thing and The map is not the territory.