Make sure decorative images can be ignored by assistive technologies

Images placed on the page for purely decorative purposes should not have a text alternative. For example, these are images that do not convey information and are not necessary for the understanding of the text. These images should be ignored by assistive technologies. Decorative graphics are best placed using CSS.

If it is not possible to place a decorative image with CSS, then the alt attribute in the <​img> element should be left empty. The alt attribute must be present, but without any text.