the w3c recommends that images that convey no information, but are purely decorative, be specified in css rather than in the html markup. however, it may sometimes be necessary to include a decorative image as an html codice_2 tag. in this case, if the image truly does not add to the content, then a blank alt attribute should be included in the form of codice_9. this makes the page navigable for users of screen readers or non-graphical browsers. if (in breach of the standard) no alt attribute has been supplied, then browsers that cannot display the image will still display something there, e.g. the url of the image, or a fixed text string.