Text Alternatives for Complex Images
Standard 'alt text' is great for simple photos, but it often fails for complex data like charts, graphs, flowcharts, or infographics.
What’s in it
What is it for?
Standard 'alt text' is great for simple photos, but it often fails for complex data like charts, graphs, flowcharts, or infographics. A single sentence cannot convey all the information provided. People using screen readers (or anyone who struggles to process dense visual data) must be able to access the same information as everyone else.
How to support it
It requires a two-step approach because a short description is not enough
- Use the standard 'alt text' to briefly identify the image (e.g. 'Bar chart showing Q3 revenue')
- Provide the full data in a text format nearby
For charts and graphs, place a properly formatted data table immediately below the image.
For infographics, provide a full text transcript or a link to a page that outlines all the information in the same order.
For diagrams, write a structured list or description that walks the user through the flow.