NO LONGER NEEDED IN BOOKWORM PUP 10.0.2 OR LATER
(already included in the .iso)
Compiled from source in Bookworm Pup I have mtPaint with webp support:-
http://smokey01.com/OscarTalks/mtPaint- ... 4-bkwm.pet
Also I have webp-pixbuf-loader which makes viewnior display webp images (pet attached below).