Couple of issues
1. thumbnail the images in Book details and Long Text editor, expand them when clicked - a'la inline images here. This may have to be optional - via a Tweak or a setting in L&F->BD.
2. add options to the Book Details context menus when an image is right clicked: Save image to disk, and Open image with.... - same as Cover.
Found a better way - stick 'em in a CAL-ATTACH.
BR