Hi Richard! Please don't hijack discussions but open a new thread for that. Otherwise the discussion becomes hard to follow in the mailing list archives.
if i install Wheezy on Powermac G4, can i then update to Stretch?
You can update it to Sid. There is no Stretch for PowerPC. To upgrade, just replace "wheezy" with "sid" in your /etc/apt/sources.list.
Or do i need to install Stretch from Netinstall to succeed?
No.
Where could i download such image?
Download "all files in zip" [1]. The ISO is contained in the ZIP file.
[1] http://jenkins.kfreebsd.eu/jenkins/view/cd/job/debian-cd_sid_powerpc/ws/
-- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaub...@debian.org `. `' Freie Universitaet Berlin - glaub...@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913