Decorative images don’t add information to the content of a page. For example, the information provided by the image might already be given using adjacent text or the image might be included for visual interest only.
In these cases, a null (empty)
alt text should be provided (
alt="") so that they can be ignored by assistive technologies such as screen readers. Text values for this type of images would add audible clutter to screen reader output or could distract users if the topic is different from that in adjacent text. Leaving out the
alt attribute is also not an option because when it is not provided, some screen readers will announce the image’s file name instead.
Whether to treat an image as decorative or informative is a judgement that only the author can make, based on the reason for including the image on the page. Images may be decorative when they are:
- Visual styling such as borders, spacers, and corners
- Supplementary to link text to improve its appearance or increase the clickable area
- Illustrative of adjacent text but not contributing information (“eye-candy”)
- Identified and described by surrounding text
Note: Where possible decorative images should be part of the CSS styling rather than being in the HTML.
Image used as part of page design
This image is used as a border in the page design and has a purely decorative purpose.
Screen readers also allow the use of WAI-ARIA to hide elements by using
role="presentation". Note that this feature is not as widely supported as using a null
Note: If the image was used to indicate a thematic break, e.g. a scene change in a story, or a transition to another topic, using the
<hr> element would be appropriate to notify assistive technology.
Decorative image as part of a text link
This illustration of a crocus bulb is used to make the link easier to identify and to increase the clickable area, but doesn’t add to the information already provided in the adjacent link text (of the same anchor). In this case a null (empty)
alt value should be used for the image.
Image with adjacent text alternative
This picture of a sleeping dog is already sufficiently described by the adjacent text. There is no need to repeat this information and a null (empty)
alt value can be used for this image.
Image used for ambience (eye-candy)
This image is used only to add ambience or visual interest to the page.
Note: If the purpose of this image was to identify a plant or convey other information, rather than to just improve the look of the page, it should probably be treated as informative. The author determines the purpose for the use of the image.