,Here are the technical specs for the cover:
Kindle Cover Requirements
• JPEG (Joint Photographic Experts Group)
• TIFF (Tagged Image File Format)
Amazon KDP applies additional compression to images when displaying them on its website. For best results, images should be uploaded with minimal compression.
Minimum 500 x Maximum 1280 pixels
Recommendations for the size of your cover art:
• Minimum of 500 pixels, horizontally
• Maximum of 1280 pixels, vertically
Save at 72 dots per inch (dpi) for optimal viewing on the web.
Product images display on the Amazon website using RGB color mode.
RGB is the color mode native to the web and most color screen displays. RGB stands for red, green, and blue. These three colors displayed at varying levels of intensity create over 16 million colors.
The RGB color space is used for product images. Use color images whenever possible and relevant. The Kindle reading device has a black & white screen today but Kindle applications for other devices, such as iPhone or PC, take advantage of colors.
Borders for White Cover Art
Cover art with white or very light backgrounds can seem to disappear against the white background. Adding a very narrow (3-4 pixel) border in medium grey will define the boundaries of the cover.
Smashwords Cover Requirements
Book cover - Required as a JPG or PNG image file. Must display the front cover of your book only, and the front cover should include the book title and authorname. Your book must have a book-like cover, because bookstores use your cover to merchandise your book in their online store. The ideal cover image is a vertical rectangle shape (like a book) with approximate dimensions of 500 pixels wide by 700 pixels tall. Images cannot be square or three dimensional.