Alt text
In one line
Alt text, short for alternative text, is a brief written description attached to an image on a web page. Screen readers read it aloud for people who cannot see the image, and browsers show it when the image does not load.
Words for a picture
An image says something, and alt text says the same thing in words. It is stored with the image, not shown on the page for most visitors. People who are blind or have low vision use screen readers that read it aloud. It also appears if an image fails to load, and search engines use it to understand what a picture shows.
What makes good alt text
Describe what the image contributes to the page, not every object in it. Keep it to a sentence or two and lead with the important part. Skip "image of" or "photo of", because screen readers already say it is an image. "A cat asleep on a stack of library books" is better than "cat".
- If the image shows a product or a piece of work, describe the features that matter.
- If it contains text, include that text.
- If it is a link or a button, say where it goes, not what it looks like.
When to leave it empty
Purely decorative images, such as a flourish or a background pattern, add nothing for someone who cannot see them. For those, the right alt text is empty, which tells a screen reader to skip the image. That is better than a long description of something that carries no meaning.
Why it is worth the minute
Alt text is one of the simplest ways to make a small website kinder to more people. It is also easy to forget, because the page looks fine without it. Write it at the same moment you add the image, when you know exactly why it is there. Our full guide to writing alt text for your website has examples for the kinds of images small sites use.
Alt text on your casa
When you add images to your portfolio or posts, give each one a short description. A casa is a small place, and a few well chosen words let everyone take part in it. You can also read about language and accessibility on Mini Casa.
Questions people ask
How long should alt text be?
A sentence or two is usually right. Put the most important detail first, and include any text that appears in the image. Very long descriptions are better placed in the page text itself.
Should decorative images have alt text?
Decorative images should have empty alt text, so screen readers skip them. Describing a purely visual flourish adds noise for people who cannot see it and gives them nothing useful.