Why is this important?
Users with visual impairments may not be able to see or interpret visual content, such as images and video. As designers you must provide text that accurately describes the nature of all visual content.
Users with hearing or cognitive impairments, and those for whom the language spoken in any video content is not their primary language, may not be able to hear or understand spoken audio in video content.
Image and video content usually requires far higher internet speeds than text, so providing text alternatives also helps users who are looking at your content with a poor internet connection.
If you are unable to associate text alternatives with images and videos, you must speak with those responsible for hosting or publishing your content, so that they can do this for you.
In this section
- All images must have a text equivalent (“Alt text”)
- Provide text equivalents for audio content
- Provide audio descriptions and text equivalents for video content
References for this section
WCAG 2.1
- 1.1.1 Non-text Content (A)
- 1.2.1 Audio-only and Video-only (Pre-recorded) (A)
- 1.2.2 Captions (Pre-recorded) (A)
- 1.2.3 Audio Descriptions or Media Alternative (Pre-recorded) (A)
- 1.2.4 Captions (Live) (A)
- 1.2.5 Audio Description (Pre-recorded) (AA)
EN 301 549 v 2.1.2
- 9.1.1.1 Non-text Content
- 9.1.2.1 Audio-only and Video-only (Pre-recorded)
- 9.1.2.2 Captions (Pre-recorded)
- 9.1.2.3 Audio Descriptions or Media Alternative (Pre-recorded)
- 9.1.2.4 Captions (Live)
- 9.1.2.5 Audio Description (Pre-recorded)
Video
- W3C Perspectives Video - Video Captions
- W3C Understanding Differences in Low Vision Activity - Integrated Audio Description & Transcript
- W3C Perspectives Video - Audio Description Example
Further reading
- WebAIM’s alternative text page
- WebAIM’s complex image tutorial
- 3 questions to Help Decide If an Image Doesn't Need Alt Text
- WAI Decorative Images
- 5 most annoying website features I face as a blind person every single day
- Deafness and the User Experience
- Accessibility according to actual people with disabilities
- Alternate text for background images
- WAI guidance on images
- WAI Alt text Decision Tree
- Text descriptions and emotion rich images
- Writing great alt text: Emotion matters
- Google – Add subtitles and captions