Import with ISBN should import book cover
In the library app, one can import books from openlibrary.org using ISBN. It works when the book is available in openlibrary, however, the cover is not imported. If you want to try, here is an example of a book with an ISBN and a cover : https://openlibrary.org/works/OL9916058W/Exercices_d'oral_en_contexte_niveau_d%C3%A9butant