Finishing up work on formatting a new book by Lisa Carver, and illustrated by Dame Darcy. The book contains 11 full-page illustrations, all black and white ink drawings. I found conflicting information regarding sizing of the images. Amazon's documentation indicated 800 x 600 pixels at 300dpi (JPG 100% quality), but the KDP forum showed some people were using larger dimensions. I wound up going with 1024 x 768.
With the variety of platforms, it looks like there is no precise way to tell what the images will look like until the Kindle book is published.