Alt text is the written description of an image in the HTML alt attribute. Screen readers read it aloud, and search engines use it to understand the image.

How to write good alt text

  • Describe the content plainly: "Golden retriever puppy on a beach", not "image123".
  • Keep it short — a sentence is plenty.
  • Skip "image of" — screen readers already announce it as an image.
  • Add keywords naturally, never stuff them.

When to leave it empty

Purely decorative images should use empty alt (alt="") so screen readers skip them.

Good alt text plus a fast, well-compressed image is the winning combo — see compress image and responsive images.