Restrictive Artwork License

[Felix Natter <fnatter@gmx.net>]

Dear mentors,

(upstream) Freeplane 1.3.x will have new icons (application icon,
document icon), but the artist wants to keep all rights and only grant
the Freeplane project all rights of use.
--> Is that ok for Debian?
--> Is it even compatible with the GPL-2+ license of Freeplane?

Thanks and Happy New Year,
-- 
Felix Natter