Amazon has updated its guidelines for ePub/Mobi files. The vendor now requires that all interior images in the ePub be high resolution (at least 300 dpi or 300 ppi). Also, Kindle does not support CMYK, so RGB should be the default color profile for cover JPEGs and internal images.
MY OLDER TITLES HAVE LOW-RES IMAGES. SHOULD I RECONVERT THEM?
While Amazon recommends redoing images in backlist titles so that they meet the current specs, this is not required at this time. If Amazon ever decides to suppress titles for having low-res images, your digital publishing representative will notify you.
HOW WILL THESE SPECS EFFECT DISTRIBUTION TO OTHER VENDORS?
Amazon’s image guidelines should not conflict with other sites’ image requirements. For example, Apple has the same requirements about using RGB color space. The main thing to be mindful of is size—image size (images should be under 4 million pixels) and overall file size (since larger files take longer to download). Also, the maximum file size for Mobi files is 650 MB.
If you have any questions about Amazon’s (or any other vendor’s) file specs, please consult your digital publishing representative.