Alt Text (Alternative Text)
Descriptive text for images that helps accessibility and image SEO.
Alt text is the written description of an image, carried in the img tag's alt attribute. Screen readers read it aloud in place of the picture, and search engines use it to understand what the image shows. Good alt text describes the information the image carries; a decorative image takes an empty alt so assistive tech skips it.
Definition
Alt text is an HTML attribute added to image tags that describes the image content. It serves three purposes: accessibility (screen readers read it to visually impaired users), SEO (helps Google understand and index images), and fallback display (shown when images fail to load).
Why It Matters
Google Images drives 22.6% of all searches. Proper alt text helps your images rank in Google Image Search and improves accessibility compliance. It also provides context when images fail to load.
Example
<img src="cwv-report.png" alt="Core Web Vitals report showing LCP 1.8s, CLS 0.05, INP 120ms — all passing" />Related Terms
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