Adding images to a Kindle book is technically easy to do in Word, but there are several guidelines you need to keep in mind regarding things like image formats and sizing. Entire books could be written about formatting images for Kindles (and indeed they have; see below), but what is covered on this page should be more than enough information for the average author.
And of course, it’s important to understand from the outset that any color images will be black and white (or grayscale, to be more precise) on Amazon’s e-ink Kindle readers.
Note: I have to give a hat tip here to Aaron Shepard’s Pictures on Kindle book, which helped me gain a better understanding of the detailed nuances and quirks of using images in a Word-based Kindle book.
As far as image formats go, you should only use JPG and GIF images in your book. Kindles can technically read formats like PNG and BMP, but Amazon will convert these into JPGs and GIFs. Amazon itself says the following:
“The Kindle file format internally supports JPEG and GIF images…” [Source].
“You can use JPG (.jpg, .jpeg), GIF (.gif), BMP (.bmp) and PNG (.png) files inside your HTML files. For best results, we suggest that you have your images in JPG format, as this offers a good compromise between size and quality. PNG and BMP files can be very large in comparison to the other size formats, and GIF files have many built-in limitations. If you are unable to upload your images in JPG format, GIF is the preferable second choice” [Source, point #7].
So in other words, while you can add BMP and PNG files to your Word document (as stated in the second quote above), they will be converted by Amazon into JPG or GIF formats (as alluded to in the first quote above). It’s not ideal to have Amazon convert your images for you, as you lose control over exactly how they look and how big they are. It’s best to do it yourself, and for that reason, you should try to only use JPG/JPEG and GIF files for the images in your book.
A lot of the documentation out there (including Amazon’s official guidelines PDF) regarding using images in Kindle books talks about how your images need to be 300 DPI (dots per inch) or PPI (pixels per inch). You can ignore this. It matters when you’re creating a print book, but it doesn’t matter on digital screens. What matters more are the dimensions of your images in pixels, like 800×600 or 1500×1200.
So just how big (in terms of pixel dimensions) should your images be? Well, that depends on a couple things. First, strangely, it depends on whether you’re using Word on a Mac or on a Windows PC. The reason for this is that the different versions of Word convert and save images at different resolutions. The Windows version of Word saves all images at 96 PPI. On a Mac, Word saves all images at 72 PPI. This means that if you are working on a Mac, the images you import into Word should be at 72 PPI or DPI. If you are on a Windows machine, your images should to be at 96 PPI or DPI. If they’re not at that minimum resolution, the images could look a bit more fuzzy than you’d like them to be.
How to determine the DPI of your images
On a Mac: Open an image in Preview, then go to Tools > Show Inspector. In the Inspector box that appears, there will be a line specifying the image’s DPI.
On Windows: Open the folder that an image is in. Right-click on the image and select Properties. Then click on the Details tab and scroll down to where it says Resolution.
This also means that, depending on whether you’re working on a Mac or Windows PC, your images will need to be different sizes (in terms of pixel dimensions) if you want them to take up the full width of the screen of the device that people are reading your book on. Tablet resolution today is around 300 PPI, and that’s another reason that Amazon has given its recommendation that all images in your Kindle book have a resolution of 300 PPI. In Amazon’s words, it’s to “future proof” your images, or make sure they’ll be compatible with higher resolution screens both now and in the future. But the reality is that your images just need to have enough pixels in height and width in them to display on high-res screens.
The Kindle app on tablets gives ebooks about 5 inches of usable width to fill up with text and images, so if you want to make sure the images in your Kindle book take up the full width of the screen, you should make them 1500 pixels wide (multiply 5 inches by Amazon’s 300 pixels number). The result will be that your image will take up the full screen width on an iPad or Kindle Fire HD, yet it will still easily be scaled down by the Kindle app when read on a smaller screen. You may want or need to make your images smaller than that, however, to reduce file size (more on that in a bit). Don’t worry, though; even an image that is, say, 1200 pixels wide will show up plenty large on a Kindle or iPad screen.
How small can your photos be? Well, Amazon has said that photos “of less than 300×400 pixels are much too small and can be rejected.” Note that this only applies to JPG images and doesn’t apply to GIFs. Amazon also says that, generally speaking, 600×800 should be the minimum size. If the images are less than about 1500 pixels wide (the number that we calculated a minute ago), they may look smaller on a large, HD screen; in other words, they won’t take up the whole width of the screen. This is especially important when you’re working with images of things like tables, graphs, and maps, where the image is essentially worthless if it is too small or blurry to read. Images like this (or photos) don’t necessarily need to take up the full width, but they still need to be large enough to be easily read.
There’s one more thing you need to keep in mind. Word does have a limit on how big your images can be. That limit is 22 inches (55.88 cm) on any side, which equates to 2112 pixels (22 in x 96 PPI) on a Windows PC and 1584 pixels (22 in x 72 PPI) on a Mac. (Note: That 22 inches number is actually the limit to how big Word documents themselves can be, but it also means that images can’t be larger than that.) Make sure that the image you insert into Word is smaller than that. If it’s bigger and you resize it in Word, Word will save it as a larger-sized GIF, even if it was a JPG before. That’s bad, because as stated earlier, you ideally don’t want Word to do any of the conversion for you if you can help it, as it can degrade the image quality and/or increase file size.
Now let’s talk some more about GIFs. When should you save your images as GIFs and when should you save them as JPGs? Well, all photos should be JPGs. Tables, charts, graphs, line drawings, and other graphics that would be vectors in a graphics editing program should be saved as GIFs. This will help preserve the sharpness of their lines. Most of what has been said above also applies to GIFs. It’s worth mentioning that Kindle books can’t display animated GIFs; the GIFs we’re talking about here are the static kind that don’t move.
Now what about the size of images (both JPGs and GIFs) in terms of kilobytes or megabytes? Is there a limit there? Yes, there is. The limit has been set by Amazon, and that limit is 127 kB (kilobytes). Your image should be smaller than that. What happens if it’s bigger? Amazon will reduce and compress the size of the image when you upload your final book file through the KDP back end. Your images should be as large as necessary (in terms of dimensions) while still trying to get under that 127 kB limit. That can be really tricky, though. Lowering the quality down to as low as 30% or 40% in a program like Photoshop (under the Save for Web & Devices option) can help, though that will obviously affect how good the image looks. If your image is larger than 127 kB (even if it’s just 127.1 kB), Amazon will automatically convert it. This resulting conversion may not look as great as you’d like it to, though, and I recommend trying to get the file size below 127 kB on your own if possible. But still, if you don’t want to mess with all of these complicated image restrictions, that may be the easiest way to go. Just insert the full-size images into your Word document and let Amazon do the heavy lifting, and be aware of the ramifications (i.e., the image not looking as good as it could).
Another thing you need to keep in mind is the total file size of your book. The larger the book’s file size, the higher the delivery costs that Amazon charges. (For more information on delivery costs, see this page on Amazon).That’s something you need to remember if you’re choosing to go with Amazon’s 70% commission tier. Amazon also has a 50 MB file size upload limit. That means that the saved .htm or .zip file that you upload through KDP needs to be less than 50 MB in size.
I realize that this is a particularly confusing issue. If you’re confused or have additional questions, contact me, and I’ll do my best to help you out.
Inserting an image
The video below shows the proper way of inserting an image in the Word document that will be your Kindle book.
Above: Inserting an image [0:57]
It’s very important that you don’t just copy images and paste them into your Word document, but that you do insert them as shown here. Also, having text wrap around your image is not recommended. The image should be inserted on a new line with nothing else on it. Any wrapped text may not look right on the different Kindles and other devices.
If you want to add captions to your images, I’ve found that the best way to go is to put regular text right below the image and make it italicized. You can do that either as a new style or manually for each caption individually. Another option is say something like, “The following image shows…” or “The above image shows….” That eliminates the need for captions entirely.
Other things to keep in mind
Your images will be left-aligned by default when you insert them in Word, but I recommend centering them for aesthetic reasons. You do that in Word the same way you center text—click or highlight it and then choose the Center Text option.
There are some Word-specific image-related quirks that we’re going to need to keep in mind and take care of. First, make sure that the “Enable PNG as an output format” box is unchecked under Web Options. In Word 2011 for the Mac, go to Word > Preferences and then click General. Click the Web Options button and then the Pictures tab and make sure the checkbox next to “Enable PNG as an output format” is not checked. Remember that we don’t want to be using PNG images because Amazon will convert them to GIFs anyway.
The second thing you need to do when working with images is prevent image resizing there in Word. What do I mean by that? Well, if you’re working in Print Layout mode (View > Print Layout), inserting an image that is too wide will cause that image to be resized to fit within the page and its margins. You don’t want this because it is yet another way in which Word automatically resizes and converts your images. There are two ways to fix it:
- Work in the Web Layout view mode (View > Web Layout), or…
- In Print Layout view mode, right-click an image after you’ve inserted it and it’s been resized to fit the page and select Format Picture. Click the Size tab or option and look for where the width and height are specified in absolute terms. Change those numbers to the size of the Original Image as shown near the bottom of the dialog box, and remember that Word as a 22-inch limit on the size of the photos you can use. (Note: You may be able to simply click the Reset button there to revert the image dimensions to their original size.) Once you hit OK, this will cause the photo to get really big and look like it’s going off the edge of the page, and that’s what you want. The images will look normal once the Word document has been converted to a Kindle document.
A cover image is an entirely different beast and will be discussed in the future in a separate module. But for know, know that it’s not necessary to include your ebook’s cover anywhere in the Word document. The cover is uploaded to Amazon separately.