Issue
If you don’t provide descriptive text for images on your website, digital document or social post, the information in those images will be hidden from some users. Alternative (alt) text is a special kind of description designed to work with technology that reads digital content aloud.
How to check
- Try to click and drag your cursor over the image. If no text highlights, it is not a readable image.
- OR, Press CTRL + F (Windows) or Command + F (Mac) and search for a word that appears in the image. If the word can’t be found in the search, the image is not readable by a screen reader.
What to do
Every time you place an image, describe what you see. One approach that can be helpful is to imagine you’re writing an AI prompt to generate a picture like the one you’ve used.
Some AI tools can analyze a photo and suggest alt text. This is fine as a starting point, but AI doesn’t understand context, so you’ll need to review any generated alt text to make sure it makes sense in your context.
Keep it concise. Eliminate “A picture of” from your description and don’t include information in the alt text that can’t be seen and understood from the picture. Try to keep the length to 200 characters or less.
- Posting on a social platform?: Check out Social Alt Text.
- Too much information to convey in a sentence?: Refer to Text description.
Recommended tools
- WebAIM: Alternative Text
- American Federation for the Blind – Writing effective image descriptions or “Alt text”
- Image alt text viewer – Simple chrome extension that toggles on to display the alt text on a page
- How Blind People use Instagram (video)
- Images & Media: Web Content Accessibility (Digital Accessibility Basic Training Canvas course)
Who’s affected
People who:
- Are blind/have visual processing difficulties
- Have slow or weak internet (alt text is what shows up on the screen if the image is slow to load)