How to make web pages accessible

Alt text is a short description of an image. Alt text is not visible on a web page, but screen readers can see it.

When to use alt text

There are two types of images - informative and decorative.

An informative image is one that helps people to understand a web page. You must add alt text to informative images.

For example, an informative image might visually demonstrate an instruction - like how to open a fire door. This image needs alt text so that people who rely on screen readers can also understand how to open the door.

Decorative images do not add important information to your content. They do not need alt text. Think about whether you need to use decorative images at all. They can make web pages look cluttered.

If you're unsure whether your image is informative or decorative, try reading your page out loud. If you need to explain the image to understand the page, it's probably an informative image. If you don't need to explain the image, it's decorative.

The World Wide Web Consortium (W3C) website explains the difference between informative and decorative images in more detail.

Why images need good alt text

Some people will not be able to see your image. For example, they may have a visual impairment. Alt text means they will not miss out on important information.

How to write and add alt text to your web page images

Informative images

Once you have added your image to your content management system, there is usually a field for alt text in the image's properties.

Or, you can describe what the image is conveying in the body text of your web page.

Decorative images

If an image does not need alt text, you can normally leave the alt text field empty. Screen readers will know to ignore the image.