Add the alternate text for images to make the image compliant with Section 508 of the Rehabilitation Act, which was enacted to make electronic and information technology accessible to people with disabilities. When you add the alternate text, screen readers or text-only readers can read the text in a tagged PDF. In DITA, we use the alt element to add additional description to images or objects like embedded tutorials. If we do not provide the necessary alt text, you cannot produce a tagged PDF on request, which might impact on making certain sales, especially Government sales.
Note:
Alt text is required only for images in the following:
End user content: User Guides, Quick Reference Guides, endpoint Installation and Maintenance guides
Overview content: Solution Descriptions, Overview and Specifications
Avoid using images that require long descriptions in the alt tag.
To limit the description in the alt tag, use callouts in a table below an image or provide a description that introduces the image. See the information on using alt text in the Accessibility section of the Avaya GIS Customer Documentation Standards (CID 156561).
Avoid puncutation marks in the description text.