Summary

Ensure that cover images include a description of any relevant information they contain.

Techniques

Examples

Example 1 — HTML cover

Only alternative text is needed when the cover contains basic information about the publication.

<img src="images/cover.jpg"
     role="doc-cover"
     alt="EPUB 3 Best Practices - O'Reilly - Pencil drawing of a goat">
Example 2 — HTML cover with description

Additional descriptive details from the cover are provided using the aria-describedby attribute.

<img src="images/cover.jpg"
     role="doc-cover"
     alt="Accessible EPUB 3 - O'Reilly - Pencil drawing of a goat"
     aria-describedby="cover-desc">
<p id="cover-desc" hidden="hidden">Best practices for creating universally usable content.
   Excerpt from EPUB 3 Best Practices</p>
Example 3 — Package document cover (EPUB 3)

The cover image is identified in the EPUB 3 manifest by the properties attribute value "cover-image".

<manifest xmlns:dc="http://purl.org/dc/elements/1.1/" …>
   <item src="images/cover.jpg"
         id="cover"
         media-type="image/jpeg"
         properties="cover-image"/>
   …
</manifest>

Frequently Asked Questions

Should I preface the alternative text with "Cover: "?

While this is a useful convention for identifying that the image is of a cover, it is not strictly necessary now that the doc-cover role exists, and may cause duplication going forward. Assistive technologies should identify that the image is the cover from the presence of this role. Support for the role is not yet widespread, however, so continued use of the preface is acceptable.

Explanation

Cover images often convey important information about a publication - more than just the title and author. A cover might give additional context, such as the publication's relation to other works. It might include a image by which the publication is commonly known (e.g., professors often refer to textbooks by key features on their covers).

Despite the importance of cover images, it is still common to find them described only by the unhelpful alternative text "cover image". Doing so disadvantages any user who cannot see the image, since they will not be able to determine if the publication matches a colloquial description.

For this reason, it is recommended to include as much pertinent information as possible about the cover in its alternative. Including any text content represented in the image is a good starting point, but also include a short description of the cover image itself, whenever applicable (e.g., some covers may not include an image, but just be a solid color).

Sometimes a lengthier description of the cover is necessary, such as when a cover shows a picture of an painting, artifact or antiquity.

EPUB 3

EPUB 3 also allows the cover image to be identified in the package document by adding the value cover-image to the properties attribute of the manifest item for the image (see example 3).

When provided, this image is commonly used by EPUB reading systems for display to the user in the bookshelf and as a splash page when loading a publication. There is no way to provide alternative text or a description for the image, but reading systems typically provide title and author information in the bookshelf to ensure that readers can access their publications.

EPUB 2

EPUB 2 similarly provides the ability to identify the cover image, but through the package document metadata:

<meta name="cover" content="manifest_cover_id" />

In this case, the content attribute references the ID of the manifest item for the image. (Note that this practice is not officially part of the EPUB 2 specification, but is recognized by EPUB 2 reading systems.)

As with EPUB 3, there is no way for authors to make these images accessible.

Related Links