I've been working with creating books, or saving altered versions of them, and I have another related question.

When I create a new book cover and spine, then import it (I've been importing them as textures), then assign them to the books and re-export/import the book under this new cover, can I delete the previously saved texture in the texture menu or does the program always need that file to draw on each time I create choose that book from the library?

My texture library is rapidly accumulating odd image files that I'd love to clear out, provided it doesn't undo my work.