Nyenyec N wrote:
What is the definitive source to read about which image
licenses are
compatible with the GFDL?
There isn't one. The closest thing to a definitive source would be the
Free Software Foundation, but they don't really address the question.
They have a detailed list of which software licenses are and are not
compatible with the GPL, but their comments on content licenses are much
more limited. They don't address the question you're getting at because
their comments are limited to software and documentation (the original
purpose of the GFDL), and images are something other than simply
documentation.
Or perhaps a GFDL text with non-GFDL images added
doesn't count as
derivative work?
This is a thorny question of interpretation without an easy answer.
However, the GFDL does allow independent works under other license terms
(including incompatible, non-free, and even proprietary licenses) to be
combined in GFDL content in an "aggregation" (Section 7 of the GFDL).
--Michael Snow