Greasy Fork is available in English.
Saves all available Preview pages from a Google Book as PNGs
< Feedback em GBookDown - Download Google Books
Used Tor 5.5.5 and Greasemonkey 3.11 and it worked like a charm, the problem was the book had non viewable pages and it didn't download them all. But that's just how it is
Saving not started after clicking 'ok' button
Saving not happend after clicking 'ok' button. I tried different plug-ins (greasemonkey, tampermonkey, violentmonkey) and different browsers.
SOLVED: Tor 5.5.5 and Greasemonkey 3.11 working