Alternative text (alt text) is vital for web accessibility. It ensures all users, including the blind, can access web content. Alt text is a written description of an image. Screen readers vocalize descriptions to assist users with visual impairments. This article discusses alt text. It covers its importance for accessibility and best practices for writing it. It also discusses its role in creating an inclusive digital space.

The Role of Alt Text in Accessibility

Alt text plays a pivotal role in making the web, digital documents, and other online resources accessible to individuals with disabilities, particularly those who are blind or have low vision. Screen readers rely on these textual descriptions to interpret and articulate the content of images. Without alt text, people who depend on screen readers are deprived of critical visual information, hindering their engagement with the content.

For instance, if a web page includes an image that provides context or supports the main message, a screen reader user would not be able to grasp the image’s relevance without alt text. Properly written alt text allows them to consume information at the same level as sighted users, creating a more inclusive user experience.

Why is Alt Text Essential for Accessibility?

1. Equal Access to Information: Alt text ensures that individuals with visual impairments receive the same information as those who can see the images. This promotes inclusivity and equal access to online content for all users, regardless of their abilities.
2. Contextual Understanding: Alt text allows users to comprehend the purpose or significance of an image, especially when the image is integral to the surrounding text or adds meaning to the webpage. For example, images such as infographics, charts, or diagrams need well-crafted alt text to convey the information they contain.
3. Fallback for Missing Images: Alt text also serves as a backup when images fail to load due to slow internet connections or technical issues. In these cases, users can still understand what the image represents through the alt text provided.

Best Practices for Writing Effective Alt Text

When crafting alt text, the goal is to provide a concise yet informative description that accurately captures the image’s essence. It should be relevant, clear, and tailored to the context in which the image appears. Below are key practices for writing effective alt text:

1. Keep It Short and Descriptive: Alt text should be brief but meaningful, ideally under 140 characters. While the description should be concise, it must still convey the necessary information. A clear description helps users understand the image without overwhelming them.
   Example:

• Correct: “A golden retriever running on a sunny beach.”
• Incorrect: “A photo of a happy golden retriever playing by the ocean on a beach at sunset.”

2. Describe the Image in Context: Consider the context in which the image appears and focus on its relevance to the surrounding content. This ensures that users with screen readers can grasp how the image contributes to the page.
   Example:

If an image shows a sales graph, a good alt text would be: “Bar graph showing sales up 20% over the past year.”

3. Avoid Redundancy: There’s no need to start alt text with phrases like “Image of” or “Picture of.” Screen readers automatically identify the element as an image. Simply describe what the image represents.
   Example:

Correct: “A running dog.”

Incorrect: “Image of a running dog.”

4. Use Empty Alt Text for Decorative Images: Not all images require alt text. Decorative images, such as page dividers or design elements, don’t add value to the content. For these, use empty alt text (alt=” “). This signals to screen readers that the image can be skipped, preventing users from being bogged down by irrelevant information.
5. Focus on the Image’s Purpose, Not Every Detail: Alt text should focus on conveying the primary message or purpose of the image rather than describing every small detail. For example, if an image showcases a product, the alt text should highlight the key features or function of the product, not the minutiae of its design.
   Example:

Correct: “Cover of the bestselling novel ‘The Great Adventure’.”

Incorrect: “A book with a blue cover, gold lettering, and an image of mountains.”

The Importance of Alt Text for SEO

In addition to its role in accessibility, alt text also plays an important part in search engine optimization (SEO). Search engines index images by reading the alt text, which helps them understand what the images are about. By incorporating relevant keywords into alt text, web developers and content creators can improve a page’s visibility and ranking in search engine results.

However, it is important to avoid overloading alt text with keywords (known as keyword stuffing), as this can detract from its accessibility purpose. Alt text should prioritize clarity and relevance for screen readers, with SEO considerations as a secondary benefit.

Example of Optimized Alt Text for SEO:

• “Gluten-free chocolate cake with dark chocolate frosting.”

This alt text provides a clear description for screen readers and also includes relevant keywords for SEO purposes.

Common Mistakes to Avoid When Writing Alt Text

• Being Too Vague or Too Detailed: Avoid vague descriptions like “Image of a dog” or overly detailed descriptions that list every element of the image. Focus on the image’s primary message or purpose.
• Skipping Alt Text for Important Images: All meaningful images should have alt text. Leaving out alt text for images that convey important information creates barriers for users with disabilities.
• Using Alt Text for Decorative Images: Decorative images should not have descriptive alt text. Use empty alt text (alt=” “) for purely decorative images, ensuring that screen readers bypass them.

Wrapping Up

Alt text is a fundamental element in creating accessible and inclusive digital experiences. It helps users with visual impairments access and engage with content by providing textual descriptions of images. Writing effective alt text requires clarity, brevity, and a focus on the image’s context and purpose. Following best practices not only improves accessibility but can also benefit SEO. By prioritizing thoughtful alt text, web designers and content creators can contribute to a more inclusive web for all.