Alt text

The photos on a small business site carry real information: the treatment room, the dish of the day, the classroom. Someone using a screen reader, or on a slow connection where images don't load, gets that information only from the alt text.

Google calls alt text the most important attribute for describing an image. It reads it together with computer vision and the text around the image to work out what the image is about. When an image is a link, its alt text also works as the link text.

• Describe what matters in the image for this page, in a short phrase. "Physiotherapist treating a runner's knee" says more than "photo" or "image1".
• Use the words people would use, without stuffing keywords. A string like "physio Leeds best physio physiotherapy" is noise to a screen reader user, and Google warns it can make a site look like spam.
• Decorative images, such as a background pattern, get an empty alt.
• If the image is a link or a button, say where it leads or what it does, not what it looks like.
• If the image contains text that appears nowhere else on the page, such as a poster with your opening hours, put the same words in the alt.

Many website builders let you add the description when you upload an image or in its settings, often in a field called alt text or image description.

1. Open a page, view its source and search for alt. Each image should have one, with words that describe it, not a file name.
2. Start with the photos of your work, your premises and your team: they carry the most information.
3. Check the file names too. Google reads them as a light clue, so knee-treatment.jpg is better than IMG00023.jpg. Our free website audit checklist covers the other checks.