Add useful alt text to images

Decide what the image contributes

Write alt text after you know why the image is on this page. A project photograph may identify a visible milestone, a portrait may identify a speaker, and a campus map may need a longer explanation elsewhere. The same file can need different alt text in different contexts. Use the image’s purpose, not the filename or camera metadata, as your starting point.

• Informative: describe the essential subject or message briefly.
• Decorative: leave the alternative empty when the image adds no information beyond nearby text.
• Functional: describe the destination or action when an image is the only content of a link or button.
• Complex: provide the key information in nearby HTML or a linked text equivalent, rather than trying to fit a report into one short sentence.

Do not mechanically begin every alternative with “Image of.” Assistive technology already identifies an image. Include that word only when it helps distinguish a photograph, illustration, or other medium.

Write and review it in the editor

In the media item or image component, enter a concise, specific alternative. Name people only when their identity is relevant and confirmed. Include location, action, or visible result when it helps someone understand the surrounding story. Keep the visible caption and alt text complementary: a caption can provide photographer credit, date, or broader context, while alt text covers what a person who cannot see the image needs for this page.

If an image contains words that are not repeated as real HTML text, do not rely on the image alone. Put the information in the page copy and use a shorter alternative that points to that context. Avoid putting event dates, registration instructions, or report findings only in a graphic.

Use the alt-text example tool to compare a draft alternative with the page context before publishing.

Know when to request a handoff

Ask the website maintenance team to review charts, maps, diagrams, image links, and any image that opens a gallery or lightbox. A chart needs its data or conclusion in text; a linked image needs a reliable accessible name; and a decorative background must not hide information. The developer should confirm that the rendered image has the intended alternative, that the alternative is not duplicated by an adjacent link label, and that the image remains understandable at zoom.