How to add a cover image to ePub and Kindle eBooks
Step 1 Place the cover picture you’d like to use in your library. It’s recommended that you use a .jpg or .png that is either 600x800 or 300x400 pixels. See: How to add an item to the library Step 2 Click the top half of the Generate help button in the Home ribbon tab. This displays the ‘Generate documentation’ window. Step 3 Select the ePub or Mobi/Kindle build you’d like to modify in the build list.