By A.J. Cosmo

Amazon offers two types of formatting options when creating books for the Kindle platform. The options allow for much different reading experiences and require different preparation before publication. It’s important to know the differences and limitations of the formats and choose one before you start work on the illustrations. Why’s that? Let me explain.

Re-Flowable Format
Re-flowable books allow users to change font sizes and even font selection at any time. It allows for links to websites, annotations, bookmarks, highlights, and more—stuff that makes an eBook different from a print book.

When you look at the code for the files, re-flowable books look like web pages. This allows for display flexibility but comes with a price. Images in re-flowable books are limited to 600×800 pixels. Those images cannot be full-screen either and will always have white padding around all sides.


This formatting option works best for high word counts and middle-grade reading levels. Picture books do not work well because you can’t float text over the images. You could put the text in the images, but the size and resolution will make the text hard to read. Alternatively, you could also make the images smaller and even, allowing for more play between the text and the images.

No matter what you do though, you will never achieve a traditional picture book look by using the re-flowable format. The programmers just didn’t have us in mind when making that one. Lucky for us, they did invent another format specifically for comics, cookbooks, and picture books.


If you want full-screen images with crisp, locked-in text, then fixed-format is for you. On Kindle, fixed format allows for images up to 800×1280 pixels, displayed either as a single full-screen image or two pages side by side.

Authors can either lock the viewing angle at horizontal or vertical, or choose unlock, making the book go from one page to two-page spread like the above example. This is the closest thing we have to classic picture books. However, due to the aspect ratio of the device, we can’t just scan print books and expect them to work. Cropping the image is often required.
little star original

little star cropped
While fixed-format allows for text pop-ups and panel zooming, it also lacks the highlighting, annotation, and hyper linking features of the re-flowable format. To make your format decision harder, fixed-format only works on color Kindle devices and apps (also known as the Fire line.) Black and white devices can’t even open these books, yet all the devices can read re-flowable format books.

So before you hire that illustrator for your next book, consider which format will tell your story best and bring your design team in as early as possible. Knowing what compositions and image sizes work best for each format will save you time, money, and the headache of editing pictures. If you know the formats well enough, then it will enhance your story, not encumber it.

This article only covers the Kindle formats. iBooks, as well as ePub 3 and 4, are different beasts.




A.J. Cosmo is the author and illustrator of over thirty self-published children’s Kindle books. He now divides his time between creating new work and helping other authors develop their careers. Reach him at