Alt Text: The Words Behind an Image
Alt text describes an image for screen readers and search engines. Learn how to describe images so they are accessible and can rank in image search.
Alt text is the short description attached to an image's HTML that explains the image for screen readers and search engines.
Who Reads Alt Text
Screen readers speak alt text aloud so people who cannot see the image still get its meaning, and search engines read it to understand what the image shows.
It is also what appears when an image fails to load, which is why a blank or missing alt attribute leaves a hole in the page.
Writing Alt Text That Works
- Describe what the image actually shows, as if to someone who cannot see it.
- Include a keyword only when it fits the description naturally.
- Keep it short, a few words to a short sentence.
- Leave the alt attribute empty on decorative images, and never stuff a keyword file name.
Alt Text and Image Search
Alt text is one of the strongest signals for image search, where the image itself is the result people click.
It works alongside the page context and file name, so a clear description on a relevant page is the whole recipe.
Weak: alt="seo-keywords-1.jpg"
The reading: tells no one what the image shows and helps nothing in image search.
Better: alt="flowchart of long-tail keyword research for an SEO content plan"
Why it works: it describes the image, matches the page's topic, and gives image search something concrete to rank.
Quick Tip
Treat alt text as a description task, not a keyword task, and accessibility and rankings both improve together.
Frequently Asked Questions
Alt Text, Bottom Line
Alt text is a short description that serves two audiences: people who cannot see the image, and search engines trying to rank it.
Describe honestly, keep it short, and the image finally gets its place in the page.