Why the change? Starting in August, Apple will require that all new ebook cover images be at least 1,400 pixels wide. Their previous minimum was 600 pixels.
Since Smashwords requires vertical rectangle (height greater than width) images, a new recommended ebook cover might be around 1,600 pixels wide by 2,400 pixels tall. Why 2,400? 2,400 is 1.5 times 1,600. Pull out a ruler and measure just about any print book and you'll get a ratio close to that. Most good-looking covers have heights that range from approximately 1.3 to 1.6 times your width. Amazon recommends a 1.6 width/height ratio, and their recommended height is 2,500 pixels. As you can see, there's flexibility here for personal preference whether you prefer wide or long. The image above left shows what a 1.5 ratio looks like. The height is 50% greater than the width.
Why is Apple requiring higher pixel counts? Most likely, it's because they want to provide ebook customers better covers for their current and future higher resolution iPads, iPhones and MacBooks. Since we think the Apple and Amazon guidelines are reasonable (they help readers with next-generation screens enjoy your covers in all their glory), we'll adopt Apple's requirements as our new minimum standards for cover images.
What happens next?
Apple's new requirement applies to new ebooks, and new cover updates. If your book is already in the Apple iBookstore with a smaller cover image, you're grandfathered in, UNLESS you try to update your cover image in the future, in which case they'll reject it. To help you get ahead of this change, Smashwords will make the 1,400 pixel minimum a Premium Catalog requirement starting on or around July 15. Like Apple, Smashwords will apply the standard to new titles and cover image updates. If Smashwords previously shipped your smaller cover to retailers, they won't require the new cover image size unless you update your cover image or republish a previously unpublished book. The minimum dimensions do not apply to the images or cover image inside your .epub file.
The Smashwords FAQ is now updated to reflect the new recommendations and requirements. The Smashwords Style Guide will be updated in the next day or two so one month from now this won't come as a surprise to people.
How NOT to create a new cover image
Don't use a photo or image editing program to enlarge your current image. That will cause pixelation (blur).
How to create your cover image
You'll find some tips in the Smashwords FAQ, though their best recommendation is to hire a professional. Unless you're a professional graphic artist, it's best to hire a cover image designer. All our pre-designed book covers are already designed to more than meet these size requirements, so you can buy with confidence. See this free ebook, The Secrets to Ebook Publishing Success, for comments on why a professional ebook cover image is so critical to a book's success.
Please share this post with your fellow authors and publishers so everyone has ample advance notice.