Checkpoint 5.8 - Core

People who are vision impaired use screen readers to 'read' a web site. These screen readers can read aloud information such as text and certain tables if they are marked up properly. However, screen readers cannot read non-text elements such as images, frames, image maps, scripts, applets or programmatic objects.

For images, alt attributes provide non-visual technologies with a description of the image that visual technologies, such as browsers, can display. Users in rural areas where internet bandwidth is limited might also turn off images to speed page download times.

Providing information without an alternative will mean that people with vision or audio impairments will not be able to access all the content. Even if content is not important, it needs to have an alternative so that these people are aware that information is not being missed.

Requirement

Provide alt attributes for every image.

Checking Tool

• Internet Explorer - AIS Toolbar: Images > Toggle Image > Alt
  This will turn all images off replacing them with the values of the alt attributes.
• Firefox - Web Developer's Toolbar: Images > Outline Images > Images Without Alt Attributes

Information Source

The original source of this information is located on the W3C web site  (www.w3.org/TR/WCAG10-TECHS/#tech-text-equivalent)