Text Equivalents

Make sure that all informative images have descriptive alt text. A good general rule for for the maximum size of an alt text length is the size of a “tweet,” or 140 characters. Anything longer should be described in a long description. It is especially important that images that also serve as links have alt text.

The procedure

  1. If you have not already done so, download and install the Firefox Accessibility Extension.

  2. After restarting Firefox you should see the accessibility toolbar at the top of the browser window. Choose the List of Images item under the Text Equivalents menu pick:

    screen shot of web accessibility toolbar text equivalent menu
  3. A pop-up window will appear containing a list of images and associated alt text:

    screen shot of web accessibility toolbar list of images
  4. Ensure that alt text is present for each informative image and that it accurately describes the intent of the image, especially if it is a link.

  5. Check to make sure that non-informative images have null or empty (alt="") values so they will be ignored by a screen reader.

  6. Make sure complicated images are described with a longdesc attribute or by inline text.

For more information, view the text equivalents best practices page.