I'd like to make a 8x11 book, with each page showing a full 8x11 image. Most of my jpg images are 11x14, with others being of various smaller sizes. If possible, I'd like the pictures to be full page sized, but I'm not sure how to do this. And, what will I loose when re-sizing smaller images? I will be using Photoshop Elements 18 to do the necessary resizing. Thanks.
Short answer
(1) on the proportions, it would be better for you to go back to your originals and re-crop to 8:11 instead of 11:14, but if you can't or won't do that, then you probably won't miss too much; and
(2) on the size (pixel counts, resolution), just upload to Shutterfly whatever you natively have and let them handle the resizing.
Fuller answer
Your JPEG images aren't 11:14 unless you've cropped them to that. Is there some reason you can't undo that crop and re-crop to 8:11? Or if that would be too much trouble, the aspect ratios aren't
that different: 1.27:1 images will be re-cropped to 1.38:1, i.e., you will only have 93% of the shorter side (before losses to both sides due to full-bleed) printed. Would that be acceptable?
As far as re-
sizing: IMO don't. You don't know--certainly not precisely, and probably not even closely--how many pixels Shutterfly will use, so just send them your files and let them resize. The odds are that they and their software will do a better job than you and your software.