If an image is merely used to set atmosphere or provide decoration, it is not always necessary or even desirable to provide a description. In such cases it is best to give that image a null description, such as null alt, as demonstrated below. (A null description informs assistive technologies that the graphic does not need description. If no description [e.g., no alt] at all is included, assistive technologies may announce an unlabeled graphic, leading the user to wonder what is missing.)