The old PythonWare library held online books for PIL and Tkinter. These are new ones, written for the code people run today.
What PIL became. A handbook with one page per module, a short tutorial, and reference tables for formats, mode conversions and filters. The whole handbook is also one PDF.
An introduction for Python 3 and the themed widgets, with chapters on a first program, events, styling and fonts, plus the table of every colour name.
Fredrik Lundh's own PIL handbook and Tkinter book are not reproduced here. They are in the Internet Archive, and the about page explains why they are not on this site.