Writing SEO-friendly alt tags is crucial for both accessibility and search engine optimization (SEO). Alt tags (also known as alt text or alternative text) describe the content of images on a webpage, making them accessible to visually impaired users while also helping search engines understand the image’s relevance to the page’s content.
Here’s how to write effective, SEO-friendly alt tags:
1. Be Descriptive and Specific
Alt tags should accurately describe the image so that users with screen readers can understand what the image conveys. Describe the image in as much detail as necessary, focusing on what’s important.
Example:
- Image: A man running on a beach at sunset.
- Alt Text: “Man running on the beach at sunset with ocean waves in the background.”
This provides enough context for both users and search engines.
2. Include Relevant Keywords
When appropriate, include keywords in your alt text to help your image rank better in search engine results. However, ensure the keyword naturally fits into the description and avoid keyword stuffing.
Example:
- Image: A pair of red running shoes.
- Alt Text: “Red running shoes for marathon runners.”
Here, the phrase “running shoes for marathon runners” is a keyword, but it is also a natural description of the image.
3. Keep It Concise
Alt tags should ideally be short, typically between 125-150 characters. This ensures that they are both accessible and easy to read for search engines. Focus on delivering a clear, relevant description without being overly wordy.
Example:
- Image: A laptop on a desk with a cup of coffee.
- Alt Text: “Laptop on a wooden desk next to a cup of coffee.”
4. Avoid Keyword Stuffing
While including keywords can boost SEO, overloading your alt text with keywords (known as keyword stuffing) can harm your rankings. Alt text should be informative and natural, not an opportunity to cram in as many keywords as possible.
Bad Example:
“Running shoes best running shoes marathon running shoes.”
Good Example:
“Red running shoes designed for long-distance marathon runners.”
5. Focus on Image Content, Not Functionality
For decorative images or images that serve a purely functional role (e.g., spacers, buttons), you can leave the alt text blank or use alt=”” to indicate that the image has no informational value. This prevents search engines from being confused by irrelevant content and improves accessibility for screen readers.
Example:
- Image: A decorative line break.
- Alt Text: “”
6. Context Matters
Consider the context in which the image appears. What is the image’s purpose on the page, and how does it relate to the surrounding text? Use alt text that reflects the image’s role and relevance to the page content.
Example:
- Image in a blog post about running shoes: A close-up shot of the shoe’s cushioning.
- Alt Text: “Close-up of cushioned sole on running shoe for improved comfort.”
This description not only reflects the content of the image but also ties into the page’s focus on running shoes and their features.
7. Avoid Using “Image of” or “Picture of”
It’s unnecessary to start alt text with phrases like “image of” or “picture of.” Search engines and screen readers already know the element is an image, so it’s better to go straight into describing the content.
Bad Example:
“Image of a dog sitting on grass.”
Good Example:
“Golden retriever sitting on grass.”
8. Describe Text in Images
If the image contains text, like a quote, infographic, or logo, include that text in the alt tag. This ensures that the text in the image is accessible to everyone and also helps search engines understand the content.
Example:
- Image: A motivational quote image that says, “Success is not final, failure is not fatal.”
- Alt Text: “Success is not final, failure is not fatal – motivational quote.”
9. Use Alt Tags for Product Images
For e-commerce websites, product images should have detailed, SEO-friendly alt tags. Include important product details like color, size, model, and brand. This helps improve the visibility of your product in image search results and enhances the shopping experience.
Example:
- Image: A blue Nike running shoe in size 10.
- Alt Text: “Blue Nike Air Max running shoe, size 10.”
10. Update Outdated Alt Text
Regularly review and update alt text to ensure that it aligns with any changes to your content strategy, keyword focus, or product details. Keeping alt text relevant and optimized can improve image ranking over time.
Final Tips:
- Prioritize Accessibility: Always think about how the alt tag will help users with disabilities understand the image. Accessibility should be the primary focus, with SEO being a secondary benefit.
- Avoid Repetition: If multiple images on the page are similar, write unique alt text for each one. Avoid copying and pasting the same alt text across different images.
- Test for Accessibility: Use tools like screen readers or website accessibility checkers to ensure your alt text is effective and understandable for visually impaired users.
By following these best practices, you can create alt tags that are both SEO-friendly and accessible, helping your website rank better while ensuring an inclusive user experience.