Alt text (short for "alternative text") is a written description of an image on a web page. It's one of the most important — and most overlooked — elements of both SEO and web accessibility.
What Does Alt Text Look Like in Code?
<img src="golden-retriever-park.jpg" alt="Golden retriever playing fetch in a sunny park">
The alt attribute is the text between the quotes. It tells search engines and screen readers what the image shows.
Why Alt Text Matters
For SEO
- Google can't "see" images — alt text is how it understands them
- Images with alt text rank in Google Images (20%+ of all searches)
- Alt text is a ranking signal for the page it's on
- AI search engines (ChatGPT, Perplexity) rely entirely on alt text
For Accessibility
- Screen readers read alt text aloud to blind and low-vision users
- Required by WCAG 2.1 (web content accessibility guidelines)
- Required by law: EAA in Europe, ADA in the US
- 300+ million people worldwide have visual impairments
For User Experience
- Displayed when images fail to load (slow connection, broken link)
- Helps users understand content even without visuals
How to Write Good Alt Text
Follow these guidelines:
- Be specific — Describe what you see: colors, actions, objects, context
- Be concise — 80-150 characters is ideal
- Be natural — Write as if describing the image to someone on the phone
- Include keywords — Naturally, not forced
- Skip "image of" — Screen readers already say "image"
Alt Text Examples
❌ alt="" (empty)
❌ alt="dog" (too vague)
✅ alt="Golden retriever catching a red frisbee mid-air at the beach"
For 15 more examples across different categories, see our Alt Text Best Practices guide.
How to Add Alt Text in WordPress
- Go to Media → Library
- Click on any image
- Find the "Alt Text" field on the right
- Type your description and click Update
Or, install SightSEO and let AI generate it automatically for every image.
Frequently Asked Questions
Do all images need alt text?
No. Decorative images (backgrounds, dividers, ornamental graphics) should use alt="" (empty alt). All informative images need descriptive alt text.
How long should alt text be?
Aim for 80-150 characters. Screen readers may truncate text over 125 characters. Be descriptive but concise.
Does alt text affect SEO?
Yes. Alt text is a confirmed Google ranking factor for image search and contributes to the overall page relevance signal.
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