The Complete Guide to Alt Text for SEO in 2024

Alt text (alternative text) isn’t just important for accessibility — it also plays a key role in image SEO. Modern search engines are much better at understanding image context, which makes writing proper alt text essential for improving visibility in search results.

What Is Alt Text and Why Does It Matter for SEO?

Alt text is a short description added to an image that helps both users and search engines understand what the image represents.

Search engine understanding: Helps Google and other search engines interpret image content
Image search visibility: Improves chances of appearing in Google Images and visual search results
Accessibility: Allows screen readers to describe images to visually impaired users
Fallback text: Displays if an image fails to load

SEO tip: Well-written alt text can help images rank better in search results and improve overall page relevance.

Alt Text Best Practices for SEO

1. Be Descriptive and Specific

Write short, clear descriptions that accurately explain what’s happening in the image.

❌ Poor alt text:

image1.jpg
photo
click here

✅ Good alt text:

Woman typing on a laptop in a modern office
Golden retriever playing fetch in a park
Red sports car parked in a driveway

2. Include Keywords Naturally

If relevant, include your target keyword — but only when it fits naturally.

Example: If your target keyword is sustainable fashion, a good alt text could be:


Model wearing a sustainable fashion organic cotton dress

3. Keep Alt Text Short

Aim to keep alt text under 125 characters so screen readers can read it clearly without cutting it off.

4. Match the Image Purpose

Write alt text based on how the image is used on the page:

Informational images: Describe what the image shows
Decorative images: Use empty alt="" when the image adds no meaning
Functional images: Describe the action (for example, “Submit form”)
Product images: Include brand, product name, color, and key details

Common Alt Text SEO Mistakes

1. Keyword stuffing

Overloading alt text with keywords hurts readability and usability.

2. Using “image of” or “picture of”

Screen readers already announce images, so these phrases are unnecessary.

3. Copying captions

Captions and alt text serve different purposes and shouldn’t be identical.

4. Leaving important images without alt text

Missing alt text creates accessibility issues and missed SEO opportunities.

Key Takeaways

✅ Write clear, descriptive alt text
✅ Keep it short and natural
✅ Use keywords only when relevant
✅ Match the image’s purpose
✅ Review and improve older content