For people who can’t see images—such as those relying on audible screen readers—alternative text, or alt text, is essential. Alt text provides a brief, meaningful description that communicates the purpose of an image. When a screen reader encounters an image, it typically announces “image” and then reads the alt text aloud, making visual content accessible to everyone.
Alt text should be succinct—just enough to convey the core idea without overwhelming the user. Simple images like photos or logos need alt text, and most authoring tools make it easy to add. Complex images, such as charts or diagrams, often require more detailed explanations than alt text alone can provide. In these cases, include a longer description elsewhere on the page so users can fully understand the information.
Avoid using images of text—such as text embedded in flyers, graphics, or logos—because they create significant barriers. Images of text cannot be read by assistive technologies, often display poorly on mobile devices, and become blurry when users with low vision zoom in or enlarge them. High-quality text remains crisp and customizable; images of text do not.
Decorative images such as icons don’t require alt text but they do need to be identified as decorative, so screen readers know to skip them.
Techniques
The Images web page on the Accessible Technology website includes detailed techniques for creating meaningful and accessible links across a variety of contexts, including HTML, Canvas, WordPress, Drupal, and Microsoft and Google applications.
Want to Learn More?
- Watch for an occasional series of short talks by Alaina Foust and Jeane Marty on accessibility barriers identified by DubBot at UW Web Council meetings. The next presentation will be on Thursday, December 4 (9:00-10:00) session.
- Check out UW’s Digital Accessibility calendar to find meetups, Lunch & Learn events, Digital Accessible Liaisons meetings, and more!
- Find self-paced options on our recent blog post Training Options to Build Your Accessibility Skills.
- For more guidance and examples, visit UW Accessible Technology ‘s Images web page as well as their Digital Accessibility Checklist, where you’ll find additional resources, tutorials, and best practices to help you design and maintain accessible digital content for everyone.