Right, now I'm in front of a computer here's a third, more detailed reply,
which hopefully addresses a lot of what Anne is asking.
A license, as I mentioned, is not a contract - although it can (and
regularly does) form part of a contract. The kinds of licenses we deal
with, though, are not part of any contract. The point about a contract is
that you enter into a direct, binding agreement with someone (or some
entity) - one that carries a legal obligation.
The free licenses we use don't do this; what they do is set out the
licensing permissions for the media.
If someone violates those licensing permissions they are not violating any
contract, the matter is purely considered under copyright law. The
copyright holder asserts that a user has violated the license terms; and
the licensee can either prove they have not, or agree the have etc.
As far as I know, it is not a requirement for you to be above the age of
majority in any jurisdiction to license your work.
This is because Copyright is considered a moral right, automatically
endowed on your creative works. Licensing that work falls under the purview
of copyright; it is the way you set out the permissions for reuse of that
When you put a work under a Creative Commons, for example, it includes this
text in the license:
Subject to the terms and conditions of this License, Licensor hereby grants
You a worldwide, royalty-free, non-exclusive,
perpetual (for the duration
of the applicable copyright) license to exercise the rights in the Work as
As you can see; this is a perpetual license.
You can, of course, stop offering the work under this license - however
anyone in possession of the work retains the license they received it
under, and could (in the case of Creative Commons) offer it online
themselves if they wish.
This is what Commons generally means by "irrevocable".
Ok this next bit is my musing; and it relates to whether Commons acts as a
host for the creator (or, more properly, the uploader) of a work OR as a
If Commons acts as a licensee then they are within their rights to refuse
to delete a properly licensed image at the request of the uploader. This is
because they have a copy of the work under a perpetual license and can use
it under the terms of that license to their hearts content.
However, if Commons simply acts as a host for the uploaders work, providing
a way for others to receive it under the specified license, then it becomes
more interesting. If the Foundation (the legal entity) has not been granted
the work under the relevant license then the uploader could assert his or
her moral right to have them remove it - essentially say "I would like to
withdraw this work".
Given the hand waviness of how this licensing stuff operates, that is
probably only an academic distinction of little practical use.
(n.b. I say uploader, of course, because if a work has been re-uploaded by
someone who is not the creator then it is up the uploader as to whether to
Which is why it is much easier to say "the license if irrevocable" when
these questions are posed ;)