So is a book cover just a decorative image, or does it merit a description?
I had this discussion with a couple of people at TPAC, and it seems like the only answer we could agree on is: it depends. It’s hard to argue that an ebook should fail WCAG conformance for not describing its cover, but there are some compelling reasons to consider adding a description.
It’s often hard to argue that covers include important information about a book, and all too often they’re found with the simple alternative text:
alt="Cover Image". In these cases, I tend to find such descriptions worthless, and that the image should just be marked as decorative. What stops me from doing so in practice is that the cover is often alone in a document by itself, so if you were to mark it as decorative, users of assistive technologies would be confronted with a seemingly-empty document.
There’s a good case to be made that the image is redundant information. The title and author — typically the only information on the cover — are also both in the metadata, and often found at least once more in the front matter (the title page). It’s also information in the book metadata, and the reader is typically aware of it before they get to the cover (although web publications have the potential to change this).
That only leaves the question of whether the cover art itself conveys any useful information. My first instinct, having published a few books now, was that it doesn’t. The publisher more often than not picks the artwork for the book, as it’s more of a marketing piece. I don’t know that a goat would have been my first choice for the EPUB Best Practices book, although I like to think it’s a reflection of it being the “greatest of all time”. When you see different publishers releasing the same book with different covers, it only adds to the decorative argument.
An interesting counter-argument was made that you can’t always dismiss the artwork, as sometimes books come to be known by their covers. Some O’Reilly books, for example, are known as well by their animal as by their title (e.g., the Camel book for Perl). This is true in other fields, as well, so providing a description could be useful. If a university prof uses such a nickname, for example, it would be helpful to a student who can’t see the cover to have the same redundancy check that they’re purchasing the right title.
Long story short, don’t always write off the cover as a simple image that only needs a basic
alt text. Consider whether there is anything unique about that could become a point of reference.