The Essential Guide to Alt Text: Making Digital Content Accessible for Everyone

September 28, 2023


In the digital age, images are an integral part of the online experience. They add context, evoke emotion, and provide visual cues that enrich our understanding of content. However, for individuals who rely on screen readers, an image without alternative text (alt text) is like a locked treasure chest: full of potential value but inaccessible. This blog post aims to shed light on the importance of alt text and how to implement it effectively, in line with WCAG 2.1 Level AA guidelines.

What is Alt Text?

Alternative text, commonly known as alt text, is a brief description that is associated with an image on a website. This text serves as a substitute for the image, conveying its meaning and purpose to users who cannot see it. Screen readers read this text aloud, allowing visually impaired users to understand the content and context of the image.

Why is Alt Text Important?

  1. Inclusivity: Approximately 285 million people worldwide are visually impaired. Alt text ensures that your digital content is accessible to this significant user base.
  2. Legal Compliance: Many countries have laws requiring digital accessibility. Properly implemented alt text is a key component in meeting WCAG 2.1 Level AA standards, which are often cited in legal requirements.
  3. SEO Benefits: Search engines can't "see" images, but they can read alt text. Well-crafted alt text can improve your website's SEO.

How to Write Effective Alt Text

Be Descriptive but Concise: The Art of Brevity and Clarity

When writing alt text, the aim is to encapsulate the essence of the image in a succinct manner. Think of it as a tweet for your image; you have limited characters to convey a meaningful message. For instance, if the image is of a dog, a vague alt text like "dog" won't suffice. A more descriptive yet concise version would be "a Golden Retriever playing fetch in a park." This gives the user a vivid understanding of what the image represents without overwhelming them with details.

Avoid Redundancy: Less is Sometimes More

In the realm of digital accessibility, redundancy is not your friend. If the image is already elaborated upon in the surrounding text, duplicating this information in the alt text serves no purpose and can be confusing for screen reader users. In such scenarios, an empty alt attribute (alt="") is not just acceptable; it's recommended. This tells the screen reader to skip the image, ensuring a smoother user experience.

Context Matters: The Chameleon Nature of Alt Text

An image is worth a thousand words, but the words you choose for its alt text can vary depending on the context in which the image is placed. For example, an image of a sunset could be described as "sunset over the ocean" in a travel blog, while the same image in a driving safety article might require the alt text "sunset affecting visibility on the road." Always consider the broader narrative or message when crafting your alt text.

Additional Considerations for Crafting Alt Text

  1. Functional Images: Images that serve a functional purpose, such as buttons or links, require alt text that describes the action that will occur when it is selected. For example, an image of a magnifying glass used for a search function should have alt text like "Search" rather than "Magnifying glass."
  2. Decorative Images: For purely decorative images that add no content or meaning to the page, it's best to use an empty alt attribute (alt=""). This ensures that screen readers will skip over the image, avoiding unnecessary distractions.
  3. Complex Images: Images like graphs, charts, or infographics often contain a lot of information that can't be easily summarized in a brief alt text. In these cases, it's advisable to provide a longer description elsewhere on the page and to use the alt text to point users to that description.
  4. Image Maps: When using image maps with clickable areas, each area should have its own alt text that describes the link's destination or function. This ensures that users navigating with a screen reader can understand the purpose of each clickable area.
  5. Text in Images: If an image contains text, that text should be included in the alt attribute. However, using text within images is generally discouraged as it can't be resized, customized, or accessed by screen readers as easily as regular text.
  6. Multiple Languages: If your website caters to a multilingual audience, consider providing alt text in different languages. This enhances the user experience for non-English speakers and makes your website more globally accessible.
  7. Length Limitations: While there's no hard and fast rule, it's generally recommended to keep alt text under 125 characters. This is because screen readers do not allow for fine-grained announcements of image alt text, so users cannot listen word-by-word or letter-by-letter to understand the information. However, the primary goal should always be to convey the necessary information, even if it requires exceeding this guideline.
  8. SEO and Alt Text: While the primary purpose of alt text is accessibility, it also has SEO benefits. Search engines use alt text to understand image content, which can help improve your site's ranking. However, keyword stuffing in alt text is discouraged as it creates a poor user experience and may be penalized by search engines.
  9. Testing and Validation: It's crucial to test your alt text to ensure it's effectively serving its intended purpose. Tools like screen readers, browser extensions, and online validators can help you audit your website's alt text.
  10. The Ethical Dimension: Beyond compliance and functionality, there's an ethical imperative to make digital spaces as inclusive as possible. Alt text is a simple yet powerful way to uphold this principle.

By understanding these nuanced aspects of alt text, you're better equipped to create a website that is both accessible and effective, aligning with WCAG 2.1 Level AA guidelines. It's a multi-faceted effort that goes beyond mere compliance to foster genuine inclusion.


Alt text is not just an optional feature; it's a cornerstone of an accessible digital world. By adhering to WCAG 2.1 Level AA guidelines, we can create a more inclusive environment that respects the diversity of all users. So the next time you upload an image, take a moment to add meaningful alt text. It's a small step with a significant impact.
By implementing these best practices, you're not just ticking off a box; you're opening up your digital content to a broader audience. And in today's interconnected world, that's not just good ethics—it's good business.

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