Writing Alt Text

Learning Objective

By the end of this chapter, you will be able to

  • Explain the purpose of alt text.
  • Begin writing alt text for images.

People who are visually impaired or have certain cognitive disabilities use screen readers to help them access the content of web pages and other digital media. Alternative text, or alt text, is descriptive text that enables these people to perceive the content of images.

Platforms and sites like WordPress, Instagram, and Twitter make it easy to provide alt text for images. But how do you write alt text?

First, consider the purpose of the image. What information does it convey? And then write a description that clearly and briefly summarizes that information.

Let’s take a look at an example.

person using a computer and screen reader
“WFE003: Jacob” by Rosenfeld Media, via Flickr, is licensed CC BY 2.0.

The alt text for this image is “person using a computer and screen reader.” This description clearly and briefly summarizes the purpose of the image: to illustrate a person using a computer and screen reader. It is not necessary to say that the person appears to be a man or that he is wearing headphones or dark glasses or a green pullover. Those details are irrelevant to the purpose of the image in this context and would only be distracting.

With alt text, context is everything! For this reason, if the caption or surrounding text suitably describes an image, it is unnecessary to include alt text.

See Alternative Text by WebAIM for more information on writing alt text. And please be assured that the more practice you get writing alt text, the more ease you will have in doing so.