Images are powerful, but search engines and screen readers can’t “see” them. That’s why the alt attribute exists. It helps describe what an image shows—so both users and bots can understand it.
If you want your site to be both accessible and optimized, learning to use image alt text correctly is a must.
What Is an Alt Attribute?
The alt attribute is a tag added to an image in HTML. It tells what the image is about. For example:
<img src="tiger.jpg" alt="A Bengal tiger walking in the jungle">
This short description helps:
- Search engines understand the image
- Screen readers describe the image to blind users
- Your page stay readable if the image doesn’t load
Why Alt Attributes Matter for SEO
Search engines rely on alt text to “read” your images. Using keywords naturally in alt text can improve your SEO for images, especially in Google Image Search.
Here’s how they help:
- Boosts your chances of appearing in image results
- Adds context to your page content
- Enhances your overall SEO score
But don’t stuff keywords—make it meaningful and relevant.
How Alt Text Supports Accessibility
Alt attributes are not just for SEO—they’re critical for accessibility.
Screen readers read alt text aloud so visually impaired users know what’s on the page. Adding alt attributes helps meet WCAG compliance (Web Content Accessibility Guidelines).
This makes your site inclusive and user-friendly.
HTML Alt Attribute Example
Let’s look at a proper example:
<img src="cake.jpg" alt="Chocolate cake with strawberries on top">
This works well because it:
- Describes the image clearly
- Is short and easy to understand
- Adds value without keyword stuffing
Best Practices to Optimize Alt Attributes
Here’s how to write better alt attributes:
- Be descriptive, not vague (e.g., say “Red vintage car” not “Car”)
- Use relevant keywords naturally
- Keep it under 125 characters
- Avoid “image of” or “picture of”—just describe it
- Never leave alt text empty unless the image is decorative
When to Leave Alt Text Empty
If the image is only for decoration (like borders or background icons), use an empty alt tag:
<img src="border.png" alt="">
This tells screen readers to skip it, improving the experience for users.
Did You Know?
Google’s Image SEO guidelines highlight that well-written alt text helps both discoverability and ranking—especially on image-heavy websites like eCommerce or blogs.
Key Takeaways
- The alt attribute helps describe images for SEO and screen readers
- It improves accessibility and supports WCAG compliance
- Writing meaningful alt text can boost your image SEO
- Always optimize alt attributes with clarity, context, and care
FAQs
What is an alt attribute in HTML?
It’s a tag that describes the content of an image for search engines and screen readers.
How does alt text help with SEO?
It improves image indexing, adds context, and can help your page rank better.
Should I use keywords in alt attributes?
Yes, but only if they fit naturally in the image description.
What’s the best length for alt text?
Keep it short—under 125 characters—and to the point.
Is alt text required for every image?
Yes, unless the image is purely decorative, in which case use an empty alt.
