My books published through CreateSpace have cover images provided by CreateSpace in
their cover creation templates. Some of the templates also allow you to upload an image you have created or own. If you have published a POD book through CreateSpace, you can use that cover image for your Kindle ebook image. I didn’t, however, since the cover photos are in color and at the present time Kindle only has black and white. I don’t know enough about images to be able to visualize what the color photos would look like in b/w.
Amazonwill provide a ‘placeholder’ image for your ebook if you do not upload a cover
image. All placeholder images are the same, except for title of book and name of author.
I used Word to create a simple cover image on a standard 8 ½ x 11 Word page, then saved it as a jpeg picture, and uploaded that. My intention was to have an image that is not generic like the placeholders, but reflects that this edition is an ebook, not the paperback. The thumbnail image is clear enough to be easily read, unlike many color photo covers I’ve seen.