Alt attributes, commonly known as alt text, play a crucial role in enhancing web accessibility, improving SEO, and providing context for images. Let’s explore the best practices for crafting effective alt attributes that serve both users and search engines.
1. Add Alt Text to Relevant Images
Not all images require alt text, but those that convey important information certainly do.
Use alt text for informative images
- Charts, graphs, and diagrams
- Functional icons and buttons
- Product images
- Infographics
Skip decorative images
For purely decorative images, use an empty alt attribute (alt=””). This prevents screen readers from unnecessarily describing images that don’t add value to the content.
2. Be Descriptive Yet Concise
The key to effective alt text is striking a balance between being descriptive and keeping it brief.
Describe the image’s purpose
Focus on conveying the image’s function or content succinctly. Consider the context of the surrounding text to ensure relevance.
Example: Instead of: “Image of a cat” Try: “Orange tabby cat sleeping on a windowsill”
Limit character count
While there’s no strict limit, aim to keep alt text under 125 characters. Many screen readers truncate longer descriptions, potentially losing important information.
3. Avoid Redundant Phrasing
Efficiency in alt text helps improve the user experience for those using screen readers.
Skip phrases like “image of”
Screen readers typically announce that the element is an image, so starting with “image of” creates unnecessary redundancy.
Example: Instead of: “Image of a red apple” Try: “Fresh red apple with a green leaf”
4. Use Proper Grammar and Punctuation
Proper grammar and punctuation in alt text ensure clarity and ease of understanding.
Write in complete sentences
Use capitalization and punctuation as you would in regular text. This helps the alt text read smoothly when voiced by screen readers.
Example: “Woman in a blue suit giving a presentation to a diverse group of colleagues.”
5. Provide Context
The same image might require different alt text depending on its context within the page.
Tailor alt text to context
Adjust your description to fit the specific context of the content where the image appears.
Example: For a company logo on the homepage: “Company XYZ logo” For the same logo in an article about rebranding: “New minimalist logo design for Company XYZ, featuring sleek geometric shapes”
6. Test with Screen Readers
To ensure your alt text is truly effective, it’s important to experience it as your users would.
Evaluate usability
Use screen reader software to test how your alt text sounds when read aloud. This can help you identify areas for improvement in clarity and informativeness.
7. Consider Long Descriptions for Complex Images
Some images, like infographics or complex diagrams, may require more detailed descriptions than can fit in a concise alt text.
Use additional resources for detailed images
For complex visuals:
- Provide a brief alt text
- Link to a more detailed description elsewhere on the page
Example: Alt text: “Infographic: 5 steps to improve website accessibility” Then provide a link to a full text description of the infographic content.
Conclusion
By implementing these best practices for writing alt attributes, you’re not only improving the accessibility of your website but also enhancing its SEO performance. Remember, well-crafted alt text serves multiple purposes:
- It makes your content accessible to users with visual impairments
- It provides context when images fail to load
- It helps search engines understand and index your visual content
Regularly review and update your alt text to ensure it remains relevant and effective. By prioritizing clear, concise, and contextual descriptions in your alt attributes, you create a more inclusive and SEO-friendly web experience for all users.
