How can you write effective alt text for images that improves accessibility?

1 Why alt text matters

Alt text is not only a courtesy for your audience, but also a legal requirement in some countries. It ensures that your content is accessible to people who use screen readers, magnifiers, or other assistive technologies. It also helps search engines index and rank your images, which can drive more traffic to your site. Moreover, it provides a fallback option in case your images fail to load or are blocked by browsers.

2 What to include in alt text

Alt text should be concise, clear, and relevant to the context of your content. It should describe the main purpose, message, or function of the image, not just its appearance. It should also include any important details, such as text, numbers, colors, or emotions, that are not obvious from the image alone. However, it should avoid unnecessary or redundant information, such as "image of" or "picture of", that adds no value to the user.

3 How to write alt text

When writing alt text, it's important to use plain and simple language that your audience can comprehend. Additionally, you should include quotation marks around the alt text to differentiate it from the other code. Furthermore, a period should be added at the end of the alt text to pause for a screen reader. It's also important to use keywords that match your content and SEO strategy, but avoid keyword stuffing or spamming. Lastly, unique alt text should be used for each image on your page, unless they are identical or decorative.

4 How to test alt text

Before publishing your content, you should test your alt text to ensure it functions properly and offers an enjoyable user experience. You can use a variety of tools and methods to check your alt text, like a screen reader or browser extension like ChromeVox or NVDA, an online validator or browser developer tool like WAVE or Lighthouse, a web accessibility checklist or browser plugin such as WebAIM or A11Y, and feedback from real users with visual impairments or disabilities. This will help you understand how they perceive and interact with your images.

5 How to improve alt text

Writing effective alt text is not a one-time task, but an ongoing process that requires constant monitoring and improvement. Whenever you change or add new images to your content, you should review and update the alt text to ensure it is performing optimally. To track and optimize image traffic, clicks, and conversions, you can use analytics tools such as Google Analytics or Search Console. SEO tools such as Moz or SEMrush can help you research and refine keywords, competitors, and trends. Accessibility tools such as AChecker or AXE can audit and enhance web accessibility standards and compliance. Finally, user feedback tools such as SurveyMonkey or Usabilla can collect user insights and suggestions to improve your alt text.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?