Open your PDF cover image in Expert Mode then create a template using the top menu:
File >> New >> Blank File
Set width and height of 13 in x 10 in (to achieve 85% coverage) and set resolution to 72 with background color white. Then click OK
Drag your book cover up onto the template.
Select the move tool from the top of the tools pallet and click on the book cover and drag to position it in the center.
Click File >> Save As
In the future if you get the file too large message you can upload the picture to http://www.pixentral.com. It accepts pictures up to 2MB.
Then post a message to this forum telling the URL of the picture at pixentral.
Wow! I can't thank you enough! There is not enough space here for me to express my gratitude for helping me! You are a saint! I had the Pdf files uploaded and stored in my organizer, so the images of the book covers appeared in the bottom of Photoshop Elements 11 Editor. I did exactly as you instructed, then sent the Jpeg to Amazon and it uploaded in less than 5 minutes. The image could be a little bigger, but now I can utilize the software enough to tweak it.Thanks so much!!!! Any other ideas would be greatly appreciated. Take care and have a great 2013!