What it looks like
<img src="rankings.jpg" alt="Two people reviewing a website's search rankings on a laptop">
Why alt text matters
- Accessibility: blind and partially sighted visitors get the same information as everyone else.
- Image SEO: it helps images appear in Google Images and adds context to the page.
- Fallback: visitors still learn what the image was meant to show if it doesn’t load.
How to write good alt text
- Describe what the image shows and why it is there, in one short sentence.
- Be specific: “Red running shoe, side view” rather than “shoe”.
- Include a keyword only if it describes the image naturally; don’t stuff keywords.
- Don’t start with “image of” or “picture of”; screen readers already announce an image.
- Use an empty alt attribute (
alt="") for purely decorative images, so screen readers skip them. - For charts and infographics, sum up the key point and explain the details in the text.
You can test whether images are missing alt text with a free web accessibility tester.
Alt text by image type
| Image type | What to write |
|---|---|
| Photo that supports the text | A short description of what is shown and why |
| Product photo | The product, colour, view and key detail |
| Chart or graph | The main finding in one sentence; give the data in the text or a table |
| Logo | The company name (and “logo” only if it helps) |
| Image used as a link | Where the link goes, since the alt text acts as the link text |
| Decorative image | An empty alt (alt=””) |
Alt text mistakes
- Keyword stuffing. Google’s image guidance warns that filling alt text with keywords is treated as stuffing.
- Missing alt text on content images.
- The same alt text for every image.
- Using the file name (“IMG_4021.jpg”) as alt text.
Alt text and accessibility rules
The Web Content Accessibility Guidelines (WCAG) ask for text alternatives for non-text content. Good alt text is both an accessibility need and an SEO help. Our guide to image SEO covers formats, size and sitemaps.
Alt text FAQs
How long should alt text be?
Usually a short phrase or one sentence. Say what matters and stop.
Is alt text the same as the image title attribute?
No. Alt text is the description used by screen readers and search engines. The title attribute is a tooltip that is not what Google’s guidance relies on.