Covers in EPUB 3

by Keith Fahlgren

Now that EPUB 3 is an IDPF Proposed Specification it seems like a good time to update some of our EPUB blog posts. One of the most popular was Best practices in ePub cover images, which helped clarify how to include a cover image for most ebook readers. While cover image markup wasn’t specified in EPUB, I’m happy to report that EPUB 3 clearly explains how to include a dedicated cover image.

Note: If you’re new to the EPUB 3 specifications, the best place to get a clear introduction to the four parts of the specification is the EPUB 3 Overview. Marking a specific image is a metadata problem at the publication level, so we’ll be referring to the EPUB Publications 3.0 specification. As expected, it includes “Publication metadata — mechanisms for including and/or referencing metadata applicable to the entire Publication and particular resources within it.”

Without further delay, here is the markup to mark an image as the cover in EPUB 3:

<item id="img24"
      properties="cover-image"
      href="the_cover.jpg"
      media-type="image/jpeg"/>

The new properties attribute is added to an otherwise “normal” OPF item and is all that’s required to mark an image as the cover. While including a cover image is still optional in EPUB 3, you may only mark one image as the cover.

Most of the metadata improvements in EPUB 3 are based on this properties attribute. Its uses range from noting that content includes MathML or JavaScript to indicating the type of publication.


If there are specific EPUB 3 topics you’d like to see us write about, please leave a note in the comments—Thanks!