A Kindle book has two cover images that serve different purposes and cause a lot of confusion:
- The cover image that displays on your Kindle or Kindle reading app
- The cover image in the amazon.com product catalog
Numerous questions posted on the Amazon Digital Text Platform (DTP) Support Forums are about the dimensions and file size of cover images, things you need to know before you can even begin to create a cover image. Most authors have some idea of what they want on the cover, but get stuck in the fog of conflicting information about specifications. My goal for this post is to sort out the specs so you can focus on creating a cover that looks professional and attractive.
The Kindle inside cover image
Some experience with using image editing software, such as Photoshop, Paint Shop Pro, SnagIt, or The Gimp, is assumed. This post focuses on image specs, not the whole process of designing a book cover.
The inside cover image looks best when it covers the entire Kindle screen. Color images are just fine. In fact, Amazon encourages the use of color because future Kindle devices will support it. Kindle reading apps for the PC, MAC, iPad, and smart phones display color now.
To achieve the best result and prevent "crunching" of your image file by DTP software, make the inside cover image a JPEG that is 600 pixels wide by 800 pixels high. While you may use a GIF or PNG image for the cover, it will be converted to a JPEG, so why not submit a JPEG, over which you have complete control?
Create and edit images in a non-lossy format! Even if the final image product will be a JPEG, create and edit images in the native format of your graphics editor until you save a copy for production. Never edit and repeatedly save a JPEG as a JPEG because the quality degrades a little with each save. In Photoshop, the procedure for saving a PSD or TIFF file as a JPEG becomes second nature with practice: Select File/Save for Web & Devices; specify Quality by using the slider or typing a number; select Optimized (NOT Progressive); select Convert to sRGB.
Experiment with the quality setting in your graphics program until you get the file size under 127KB, the upper limit allowed by Amazon’s latest Kindle Publishing Guidelines. The quality may vary from 40 to 80, depending on the amount of detail in the image. A setting between 60 and 70 works for all but the busiest images and will look crisp on the Kindle.
The canard to make your Kindle images 300ppi (or 300dpi) is repeated in the Amazon formatting guidelines and regurgitated on the DTP Forum quite frequently. (I’m going to use “ppi” because I think in pixels per inch instead of dots per inch, which are more relevant for print media). The cover image needs to be 600×800 pixels, period. The dimensions and file-size are important. Resolution is not. Other images that you create for inside the book need to fit within the viewing area and be under the file-size limits. If you submit 300dpi images with your Kindle book files, they are likely to be big files with big dimensions, and they will definitely be resized and compressed to fit the Kindle or app viewing area. As compression increases, quality decreases and images become pixelated; it’s better to use illustrations that won’t require serious compression or resizing.
Why is it important to comply with file size guidelines?
If you use Kindlegen to build your final eBook as a .mobi package, an image at or over 127KB will be compressed further by Kindlegen or Amazon’s DTP. Compression lowers quality.
If you use MobiPocketCreator to build your final eBook as a .prc package, images over 63KB will be smushed. MPC has not yet caught up with the new guidelines. Nevertheless, many simple book covers will look great at 63KB or less. An elegant cover can be achieved with a solid color background, nice typography, and a central design element. Fewer colors and line drawings keep file size down.
Example of a cover image under 60KB
If you publish a series or want a similar look for all your books, create an image in a graphics program that supports layers. That way, you can reuse the basic image and easily change the title and author, add an optional illustration, your logo, and some standard text.
Click thumbnail to view the full-sized image.
HOT TIP! Let MobiPocketCreator do the heavy lifting and use Kindlegen for your final “build.” If your book has many large illustrations, save time and effort by creating your project in MPC. Add your files, metadata, and guide, and save the project. When you do this, MPC creates a valid OPF file for you. Then run Kindlegen against the MPC-generated OPF file for the final build. KG usually accepts the MPC-generated OPF file without whining. If the file name contains spaces, enclose it in quotation marks (example: "my great novel.opf"). Alternatively, copy the OPF to a new file without spaces in the filename.
If you simply zip your HTML files and images for uploading to Amazon DTP, do keep the inside cover under 127K. There have been rumors that DTP does not yet honor the larger image size, but it’s reasonable to expect compliance by Amazon for it’s own software, sooner rather than later. Doing so is in their best interests.
The Amazon catalog product cover
The cover that appears on amazon.com can be uploaded as a JPEG or TIFF file, up to 1280 pixels high. It must be at least 500 pixels wide.
Why create such a huge image when the catalog thumbnail is teeny?
Zoom and pan!
You have, no doubt, seen fancy covers in the Kindle store that you can click to zoom and pan. If you submit your 600×800 pixel inside cover image as the product cover, you lose zoom and pan and deprive potential readers of the heady experience of viewing your cover image in all its glory. If the cover has great detail, the product image may be the best way to see it.
There is some wiggle-room in the ratio of width to height. However, it’s convenient and eye-pleasing to create a cover image of 900 by 1200 pixels for use in the Amazon catalog. This size is easily set to 600×800 pixels at 72ppi or 96ppi for the inside cover. There is also another simple, bulletproof way to use one image for both the Kindle and product cover without scaling, cropping, or selecting a rectangle with a set ratio.
Bulletproof cover size
If you want to keep the same width to height ratio for the product image and the Kindle cover, make the original image 938px wide by 1250px high, at 150ppi, a good size for the product image. When you change the resolution to a web-friendly 96ppi, it will resize automagically to 600px by 800px, which is perfect for the inside Kindle cover.
If you’re thinking, “Whoa, what a big image!” hang on a second. Understand that the product cover will always be processed by DTP after uploading. It will become the source for a JPEG thumbnail and a larger image, with even more detailed zoom and pan effects. For this reason, I prefer to upload a 150ppi TIFF image instead of a JPEG, which, as we have noted, degrades a bit every time it is manipulated and saved.
If you prefer, you can upload your product image as a JPEG, at 72ppi or 96ppi. While 72ppi is still often recommended for web work, standard monitors have displayed content at 96ppi for many years. If I went with JPEG, I would use 96ppi.
Example of a detailed cover image
I’m using the cover of my “learning lab” Kindle publication, Irish Fairy Tales, since it has several common features: a detailed color image, a display font, and a solid background. Both images below are JPEGS, 600 pixels wide by 800 pixels high. The first one has a file size of 126.1KB and a quality level of 68. The second, 63.13KB and a quality level of 33. If you click the thumbnails to view the full images, the quality difference should be apparent, especially in the details. Artifacts will be noticeable around the text in the 63KB image.
The product cover image was submitted as a 900×1200 .tif file at 150ppi and a file size of 1.12MB. When saving a TIFF format copy for uploading, save as a flattened image, without preserving multiple layers. They are not necessary and a flattened image will be a smaller file. LZW compression is standard.
Why is the "zoom and pan" feature important?
Cover image zoom and pan in the Amazon catalog lets potential readers see minute details of the cover image. It’s more interesting and fun than looking at a smaller, mushier image. It shows that you care about the quality of their experience. If illustrations are an important feature of your book, a high-quality cover hints at the professionalism of the images they will find inside.
Examples of covers with zoom and pan
Irish Fairy Tales, by James Stephens, illustrated by Arthur Rackham. This is a favorite book I formatted and optimized for the Kindle as a learning experience. The cover and other illustrations are enhanced scans from my personal copy of the London, 1920 edition. An illustrated book is very challenging and I chose the Frontispiece for the cover because I wanted it to be a good representative of the care that went into optimizing its gorgeous Arthur Rackham illustrations for the Kindle.
Huckleberry Finn, from Allan Classics, displays a much larger version of the original Photoshop file in the Kindle catalog than for the inside book cover. Even if you create your book files with MobiPocketCreator or have a Kindle cover image under 63KB, it’s a good idea to make the original image 900 by 1200 pixels (or 938 by 1250 pixels) to take advantage of zoom and pan. The line drawing is on a layer tucked between the logo and the background. Text, as always, is on separate layers that can easily be changed. Photoshop’s vector text layers scale perfectly and stay sharp.
Surviving Xcarion, by R. G. Chandler has a cover derived from an extremely detailed pencil drawing. The author provided a TIFF file of the drawing and requested a specific font for the text. The drawing itself has a beautiful soft look that is low contrast and literally disappeared when viewed at the size and resolution required by the Kindle. The final Kindle cover has an increased dynamic range and higher contrast. The best view is with zoom and pan. Add a background under text instead of overlaying it directly on a busy drawing if you have a choice.
Turning This Thing Around, by Keith Maginn. This cover is much less detailed, with a smaller file size, and a solid black background for drama. It looks very sharp on the Kindle device and when zoomed. The cover was based on the author’s request for the drama symbols to echo title meaning. Typography and simple shapes can make a strong statement, and should be considered, along with other options, particularly when photos of the book’s subject or author are not available. I would not use an outline font again, though, because it breaks down in thumbnails.
Kindle display specifications
Kindle New Generation display
6″ diagonal paper display, with latest generation E Ink Pearl technology, 600 x 800 pixel resolution at 167 ppi, 16-level gray scale. 50% better contrast than previous models. Optimized with Amazon’s proprietary waveform and font technology to make pages turn faster and fonts sharper.
Kindle DX display
9.7″ diagonal paper display with latest generation E Ink Pearl technology, 1200 x 824 pixel resolution at 150 ppi, 16-level gray scale, new 10:1 contrast ratio.