How to write image alt text for every meaningful image
Every meaningful image needs alt text that describes it in one short sentence, while purely decorative images get an empty alt attribute. Alt text helps blind visitors, appears when an image fails to load, and gives search and AI engines context about what the picture shows.
By ratemysite.ai editorial team. Updated .
How do you fix it?
- List the images that have no alt attribute, using the audit result or your browser accessibility panel.
- For each meaningful image, write one sentence that says what it shows and why it is there, such as "Bar chart of monthly signups rising from 200 to 900".
- Set alt="" on decorative images such as dividers and background flourishes so screen readers skip them.
- Avoid starting with "image of" and avoid stuffing keywords.
- Re-run the audit and confirm the Image alt check passes.
What is alt text?
Alt text is the value of the alt attribute on an image tag, a short written description of the picture. Screen readers speak it aloud, browsers show it when the file fails to load, and search engines use it together with the file name and nearby text to understand the image. The WebAIM Million study, which scans one million home pages each year, regularly finds that more than half of home pages have at least one image missing alt text.
How do I decide what an image needs?
Ask what the visitor would miss if the image vanished. If the image carries information, such as a product photo, chart or screenshot, describe it. If it only adds decoration, use an empty alt so assistive tools skip it. For an image that is a link, describe the destination, not the picture. Write for a person who cannot see the page, and keep each description specific: "Red running shoe, side view" beats "shoe".
How much does this check matter?
- This check is worth about 1% of the overall score.
- A finished report is reused for 24 hours before you can re-analyze it.
- Each page is fetched with a timeout of 10 seconds, and HTML larger than 2 MB is not audited.
What else do people ask?
- How long should alt text be?
- Keep it under about 125 characters. If a chart needs more explanation, put the details in the surrounding text.
- Is alt text the same as the image title?
- No. Alt text is read in place of the image. The title attribute is an optional tooltip and is not a reliable substitute.