Web guidelines for content editors: Alternative text for images

Alternative text (sometimes just called “alt text”) is the simplest way to improve accessibility to your pages that contain images. Alt text is meant to replace images – not augment them. It is utilized by people who either cannot see your page or have low-vision such that the alt text replaces or attempts to describe what is being shown in the image.

From WebAIM:

Alternative text serves several functions:

  • It is read by screen readers in place of images allowing the content and function of the image to be accessible to those with visual or certain cognitive disabilities.
  • It is displayed in place of the image in browsers if the image file is not loaded or when the user has chosen not to view images.
  • It provides a semantic meaning and description to images which can be read by search engines or be used to later determine the content of the image from page context alone.