Using the graphics from http://reinerstileset.4players.de/englisch.html came up in the IRC channel last week.
We were looking in particular at the trees he has done. Trees are present in a few sections on the site - there are some growing in the animated section. It's an interesting site to dig around.
The licensing terms for the graphics lack desirable hard edges though: http://reinerstileset.4players.de/readmeE.html
I took an action to contact Reiner and clarify if we can release his graphics under the GPL. The short answer is that we can't re-license the graphics under the GPL but we can (if we note reiners license terms with the files) distribute and modify them almost without restriction.
Here is my email to Reiner:
I'm working with a community making an open source game (http://wl.widelands.org) and we'd love to use some of your graphics for trees and growing trees in the game.
We are slightly confused by your licensing terms. Our game is GPL and what we'd really like to do is to include a few of the trees, with the game, and still be able to release all our sources under the GPL.
Reading your README where you talk about the licensing this sounds like it would be OK?
Do you have the time to clarify that for us because we really love the graphics!
Many thanks for providing such an excellent resource to the community!
Ryan and the Widelands team.
And here is his reply:
Well, its easy in the end. You have of course the permission to use the graphics. Thats why they are available. Your game is under GPL then, and the game is completely yours. You can do with it what you want. You could even sell it. But the copyright at the graphics stays still in my hands
This means for example, you can use the graphics to build your game. And a user of your game can even grab and use the graphics from your game to make his own game too. But he is not allowed to unbundle the graphics from the game and provide just the raw graphics then.
I will never charge a fee. The graphics are and stay freeware. I am only interested in preventing abuse. So don`t worry too much
Good luck with your gameproject
All the best
I think Reiners intention there is clear - he even says on his site that you have "full ownership" of the graphics once they are embedded in your game.
However, obviously, so long as Reiner retains some hold over the usage of the files (namely that they may not be extracted from the game and hosted in gallery form akin to his website) then we are not totally in ownership of the graphics and thus not able to truly release them under the GPL.
We are however free to use and distribute any of his graphics as part of our software. Modification and distribution ad infinitum is fine - Reiners restriction is that the graphics are not extracted into a gallery form.
I would suggest the best course of action be as follows: 1) Create a separate directory for graphics from Reiners site. 2) Include his licence / README / above letters as the license for files in that directory. 3) Note that that directory is under a separate license in our main licence file.
Note that we would also have to refrain from including Reiners graphics in any gallery pages we might have that dump all the graphics we use.