Design Alt Text That Carries Meaning

Accessibility · accessibility, microcopy

Updated 2026-07-28

Write alt text for the job the image is doing, not for what the image contains. The same photograph needs different text on a product page, in a case study, and inside an avatar.
Mark decorative images as decorative. A background texture, a divider, or a shape that repeats the adjacent heading should be skipped entirely rather than described.
Describe the destination for images that act as links or buttons. If an icon opens settings, the text is "Settings", not "gear icon".
Put the data in the text for charts and diagrams. Alt text cannot carry a full dataset, so summarize the finding and link to a table or description that has the numbers.
Do not start with "image of" or "picture of". Assistive technology already announces that it is an image, so the prefix wastes the first words of every description.
Keep it to one useful sentence where you can. Long descriptions belong in the surrounding copy, where everyone benefits from them.
Never ship a filename as alt text. An automatic fallback that reads out a hash or a camera filename is worse than an empty description, because it cannot be skipped.
Make alt text a required field wherever users upload images, and explain why in one line so it does not read as bureaucracy.

Good alt text is a writing task with a UX goal, which is why it cannot be generated as an afterthought.