What is the importance of image accessibility in DITA documentation?

Image accessibility in DITA documentation is of paramount importance as it ensures that all users, including those with disabilities, can access and understand the content. Proper image accessibility, achieved through techniques like providing alt text, is a legal requirement in many regions and aligns with inclusivity and usability standards.

Image accessibility in DITA documentation refers to the practice of making images, charts, and other visual elements comprehensible to individuals with disabilities, such as those who are blind or have low vision. It is crucial for several reasons. First, it ensures legal compliance with accessibility laws like the Americans with Disabilities Act (ADA) and the Web Content Accessibility Guidelines (WCAG). Second, it promotes inclusivity by allowing all users to access and benefit from the content. One common way to achieve image accessibility is by using the “alt” attribute in DITA to provide alternative text descriptions that convey the image’s content and purpose. For example, in a DITA topic about a product, if there’s an image of the product’s packaging, providing an alt text description like “Product X packaging” ensures that individuals using screen readers can understand the image’s context.

Legal Compliance

Image accessibility in DITA documentation is vital to comply with accessibility laws and guidelines. Many regions, including the United States, have enacted laws such as the Americans with Disabilities Act (ADA) and Section 508 of the Rehabilitation Act that require digital content, including documentation, to be accessible to individuals with disabilities. Failure to provide accessible content can lead to legal consequences, making image accessibility a legal requirement for organizations.

Inclusivity and Usability

Beyond legal obligations, image accessibility is a matter of inclusivity and usability. Ensuring that individuals with disabilities, such as those who are blind or have low vision, can access and understand content is a fundamental aspect of providing equitable access to information. By making images accessible, DITA documentation becomes more inclusive, allowing a wider range of users to benefit from the content, which is essential for education, training, product support, and more.

Alternative Text (Alt Text)

The most common method for achieving image accessibility in DITA is through the use of the “alt” attribute. This attribute is added to image elements and provides a textual description of the image. When an image is inaccessible, as is the case for screen reader users, the alt text is read aloud, allowing users to understand the image’s content and context. For example, in an instruction manual, an image showing a button press can have alt text like “Pressing the ‘OK’ button.”

Visual Impairment and Screen Readers

Consider individuals who are blind or have visual impairments and rely on screen readers to navigate digital content. When a screen reader encounters an image, it reads the alt text aloud, making the content understandable. Without alt text, the image’s content is lost to these users, hindering their ability to follow instructions, learn from visuals, or understand the context. Properly crafted alt text ensures that the image’s purpose and message are conveyed effectively.


A DITA user manual for software contains screenshots to illustrate the interface. To ensure image accessibility, authors add alt text descriptions for each screenshot using the “alt” attribute within the image element.

  <title>Application Interface</title>
  <image href="screenshot.png" alt="Main application interface displaying the dashboard"/>

In this example, the “alt” attribute provides a text description of the image, explaining that it shows the main application interface displaying the dashboard. This description ensures that individuals with visual impairments using screen readers can comprehend the content, and it aligns with accessibility standards and regulations, making the DITA documentation more inclusive and legally compliant.