
If two people
collaborate and produce a single picture, then as others have noted, they are
“joint authors” and they jointly own the associated copyright. Among other
things, that means a single author can unilaterally license the work to anyone
and on any terms the single author sees fit. (There is, however, a requirement
to share licensing revenue, if any, with the other coauthor(s).)
Copyright in Vietnam
But you might
be asking...