(okay with US and Czech laws, ie. explicit permission
needed; okay with
GFDL, ie. can be nonderivative; no free image available; fair use-like
rationale)
If explicit permission is needed, then people can't reuse the content.
One of the most important things about Wikipedia, in any language, is
the possibility of reuse. It may be legal, but it doesn't seem worth
it to me.