Alternative text (alt text) is one of the most fundamental aspects of web accessibility. It ensures that images on a website are accessible to people who use screen readers, as well as those with slow internet connections or technical issues that prevent images from loading. Despite its simplicity, many websites either neglect or misuse alt text, creating barriers for users with disabilities.
In this post, we’ll explore why alternative text is essential, how to write effective alt text, and best practices for implementation.
Why alternative text matters
Accessibility for visually impaired users
Many users rely on screen readers to navigate the web. When an image has descriptive alt text, the screen reader reads it aloud, helping visually impaired users understand the image’s purpose. Without alt text, a screen reader may skip the image or announce it as “image” or “unlabelled graphic,” which provides no meaningful information.
Enhancing usability in different contexts
Alt text is useful beyond accessibility—it improves usability in situations where images can’t be displayed. This includes slow internet connections, browsers with images disabled, or email clients that block images by default. Providing alt text ensures users still get the necessary context.
SEO benefits
Search engines cannot “see” images but rely on alt text to understand their content. Well-written alt text can improve a website’s search engine rankings, making images discoverable through image search and improving overall SEO.
Compliance with accessibility standards
Alt text is a requirement under accessibility laws such as the Web Content Accessibility Guidelines (WCAG) and regulations like the Americans with Disabilities Act (ADA). Failing to provide alternative text can result in legal consequences, especially for businesses and government websites.
How to write effective alternative text
Be descriptive and concise
Alt text should clearly describe the image’s content while keeping it brief. A good rule of thumb is to describe the image as if explaining it to someone who can’t see it.
Example:
❌ Bad Alt Text: IMG_1234.jpg
✅ Good Alt Text: Golden retriever puppy playing with a tennis ball in a grassy field.
Convey the image’s purpose
Not all images require a literal description. If an image conveys an action or meaning, describe its function rather than just its appearance.
Example:
For a search icon:
❌ Bad Alt Text: Magnifying glass icon
✅ Good Alt Text: Search the site
Avoid redundant phrases
Screen readers already announce that an image is present, so phrases like “image of” or “picture of” are unnecessary.
Example:
❌ Bad Alt Text: Image of a woman smiling and holding a coffee cup
✅ Good Alt Text: Woman smiling and holding a coffee cup
Leave decorative images empty
Not all images need alt text. If an image is purely decorative (e.g., a background image or a decorative border), use an empty alt attribute (alt=""). This tells screen readers to ignore the image, reducing unnecessary distractions.
Use keywords naturally
Since alt text contributes to SEO, including relevant keywords can be beneficial—but they should fit naturally within the description. Keyword stuffing can harm both accessibility and SEO.
Example:
For a blog about healthy smoothies:
✅ Berry smoothie in a glass jar with a straw, surrounded by fresh strawberries and blueberries.
🚫 Avoid: Berry smoothie healthy drink fruit smoothie best smoothie recipe.
Best practices for implementing alternative text
- Always provide alt text for meaningful images. Ensure all content images, such as photos, infographics, and product images, have useful alt text.
- Use empty alt attributes (alt="") for decorative images. This prevents screen readers from reading unnecessary content.
- Do not use alt text for text-based images. Instead, use real text whenever possible for better accessibility and SEO.
- Keep alt text concise (125 characters or fewer). Long descriptions should be placed in nearby captions or linked to a more detailed explanation.
- Regularly audit and update alt text. Websites evolve, and images change. Periodic checks ensure alt text remains relevant and accurate.
Conclusion
Alternative text is a simple yet powerful way to make websites more inclusive. By providing meaningful alt text, you enhance accessibility, improve usability, boost SEO, and comply with legal standards. All the websites I build ensure that you can add alternative text to images when creating your own content. In fact, adding alt text is required, helping you provide meaningful descriptions with ease.