How Do You Ensure Images Are Accessible According To WCAG Guidelines?

Story Based Question

You’re building a website for a local museum that offers virtual tours of its exhibits. The site features numerous images, including historical artifacts, artwork, and educational materials. You want to ensure that the site is accessible to all users, including those with disabilities, while complying with WCAG (Web Content Accessibility Guidelines). How can you make sure that all the images on the site meet WCAG accessibility standards and improve the user experience for everyone?

Exact Answer

To ensure images are accessible according to WCAG guidelines, you need to provide meaningful alternative text (alt text) for all images, use appropriate color contrast, and avoid using images that convey critical information without proper text alternatives. You should also consider using captions, ensuring that image maps are accessible, and following the principle of “content should be accessible without requiring sight.” Additionally, images should be resizable and have proper contrast to be easily distinguishable by users with various impairments.

Explanation

The WCAG guidelines are designed to make web content more accessible to people with disabilities. When it comes to images, several key principles must be followed to meet WCAG standards.

1. Alt Text: Every image on your website should have descriptive alt text that provides the content or function of the image. This is essential for users with visual impairments who rely on screen readers to navigate the site. The alt text should be clear, concise, and meaningful, describing the image in a way that conveys its purpose. For example, an image of a museum artifact should have alt text like “Ancient Greek vase from the 4th century BC.”
2. Color Contrast: WCAG requires that there is enough contrast between text and its background, including images with text overlaid. If your images have text, make sure the text is easy to read by providing sufficient contrast. You can use online tools like the WebAIM contrast checker to assess color contrast.
3. Avoid Meaningless Images: WCAG guidelines emphasize that images should not convey important information without providing text alternatives. For example, if an image of an artifact is purely decorative, it should have an empty alt attribute (alt="") to signal that it carries no meaningful content. Images that do convey information, such as an infographic or chart, should have clear alt text that explains the data or meaning of the image.
4. Image Maps: If you use image maps (interactive images where you click on parts of the image), make sure they are accessible. Use alt attributes for the clickable areas, and ensure that the interactive elements have keyboard accessibility, so users who can’t use a mouse can still navigate the site.
5. Captions and Transcripts: If an image includes complex information, like an infographic, it’s helpful to provide a text-based description or caption. For videos with images, ensure captions are available for users with hearing impairments. This ensures that all users can access the content without requiring sight or hearing.
6. Resizability and Responsiveness: Images should be flexible and resizable to work on different screen sizes. This is particularly important for users with low vision or those who rely on screen magnifiers. Ensure that your images do not break the layout of the page when resized.
7. Descriptive File Names: File names should be descriptive and reflect the content of the image. For example, “museum-exhibit-vase.jpg” is more informative than “image123.jpg.”

By adhering to these guidelines, you ensure that your images are accessible to users with different disabilities, which improves overall user experience and helps meet WCAG standards.

Example

Let’s say you’re creating a page about ancient artifacts for the museum’s website. The page includes an image of an ancient Egyptian sarcophagus. According to WCAG, you would ensure the following:

1. Alt Text: The image should have alt text like: alt="Ancient Egyptian sarcophagus with hieroglyphics on the sides". This helps visually impaired users understand the image.
2. Color Contrast: If the sarcophagus image includes text overlaying the image, you need to ensure the text stands out clearly from the background. Use a color contrast tool to check that the text is easily legible.
3. Avoiding Decorative Images: If there are decorative images on the page, such as borders or background patterns, they should have an empty alt attribute (alt="") to ensure screen readers ignore them.
4. Image Map Accessibility: If the page uses an interactive image map of the sarcophagus with clickable areas representing different parts of the artifact, ensure that each clickable region has alt text describing its function. Also, ensure that the areas are navigable using keyboard controls.
5. Captions or Transcripts: If the page features a detailed chart or diagram explaining the historical context of the sarcophagus, include a caption below the image that provides additional context, like: caption="Diagram showing the different sections of the sarcophagus and their significance in Egyptian burial practices."
6. Resizability: Ensure the image is responsive, so it resizes appropriately on both mobile devices and desktops without losing clarity or breaking the layout.

By following these steps, the image of the sarcophagus becomes accessible to a broader audience, including people with visual impairments, and it’s also optimized for SEO.