Last Updated on 12 months ago by School4Seo Team
📘 What Is an Alt Tag?
The alt tag (technically called the alt attribute) is used in HTML to describe the content and purpose of a visual element, most commonly images. This text is:
- Displayed when the image fails to load
- Read by screen readers for visually impaired users
- Used by search engines to understand the image context
Example:
<img src="example.jpg" alt="Google Search Console Dashboard Screenshot">
✅ Why Alt Tags Matter
🔹 1. Improves Accessibility
Alt text helps screen readers narrate what’s visually displayed, making your website usable for all visitors, including those with visual disabilities.
🔹 2. Boosts Image SEO
Search engines can’t “see” images. Alt text is how they interpret what the image is about — and it helps your image rank in Google Images, featured snippets, or visual SERPs.
🔹 3. Provides Context When Images Don’t Load
If an image fails to load due to a slow connection or error, the browser displays the alt text instead.
💡 Best Practices for Writing Effective Alt Tags
| Do | Don’t |
|---|---|
| Use descriptive and concise text | Keyword stuff unnecessarily |
| Include relevant keywords only if natural | Start with “image of…” or “picture of…” |
| Describe the image’s function or purpose | Leave alt text blank for meaningful visuals |
Use empty alt (alt="") for purely decorative images | Ignore accessibility requirements |
🧠 Example Alt Text
Good:
<img src="seo-report.png" alt="Monthly SEO performance report in bar chart format">
Bad:
<img src="seo-report.png" alt="seo seo seo seo seo report report"> <!-- Over-optimized -->
🚫 When to Use Empty Alt Tags
For decorative images like:
- Spacer GIFs
- Horizontal lines
- Bullets or icons
- Background separators
Use an empty alt attribute:
<img src="divider.png" alt="">
“If the image is used to create bullets in a list, a horizontal line, or other similar decoration, it is fine to have an empty
altattribute (alt="")”
— W3C Guidelines on Alt Attributes
Also, decorative visuals should ideally be implemented using CSS (list-style-image, border-bottom, etc.).
📌 Alt Tags and SEO Strategy
- Add alt tags to all featured images, infographics, and screenshots
- Include primary or secondary keywords when it’s natural and relevant
- Don’t duplicate the same alt text across all images on the same page
- For images with links, the alt text works similarly to anchor text
✅ Final Tips
- Think of alt text as both an accessibility requirement and an SEO enhancement
- Write it for users first, search engines second
- Always test with screen readers if accessibility is a core requirement for your site