For an ebook, you will need two separate files – a high-resolution JPG cover (used for display on retail partners’ websites) and an EPUB file of the interior. Specific guidelines for each are listed.
For display use on retail partners’ websites.
-- The file must contain the front cover only. Full-spread print book jackets that include a spine and back cover will be rejected.
-- Format: Must be a JPG file.
-- Size: 2560 pixels on the longest side. Minimum 1600 pixels on the shortest side.
-- Color: All front covers must be RGB.
The content of the cover image must not infringe another publisher’s or artist’s copyright on the same cover.
-- Size: 100MB or less. (Please note, while Lightning Source and retail sites can accept 100MB files, the IDPF Validator cannot check files over 10MB due to the amount of time it would take.)
-- Format: The file must be EPUB 3.0.0 compliant (flowable text only). We cannot accept fixed format or enhanced EPUB files at this time.
-- No single image inside an EPUB can be greater than 4 million pixels. (Total pixels = length in pixels x width in pixels).
-- Include an internal cover image This should be formatted the same size, and as part of your interior. (For use within the book content.)
-- Be sure the metadata entered in Lightning Source matches the information on your cover. For example, if the cover art and the book asset are for a book titled Paradiso, but the metadata is for Purgatorio, then the items do not match.
-- There should not be any reference to page numbers in the book. This includes the Table of Contents. Your e-book will never look just like your print book. E-readers are limited in the way they display content and your book will appear different from device to device.
If using a third-party ePUB provider, we highly encourage you to verify that the files created will be suitable for production or manufacturing, and are not for personal use only.
One way to tell if your file is valid before uploading is by running your file through IDPF’s free ePub Validator (http://validator.idpf.org/). Be aware, that this tool only accepts files up to 10 MB. If you have any problems using the epub validator tool you can also try this one: https://www.pagina.gmbh/produkte/epub-checker/