Question about GPL
Hello! I'm having some trouble understanding the GPL license and hope I can get some help. Let's say I'm developing a game that I want to sell and in this game I use ONE single picture with GPL license (the rest is my own work). What of the following is true?
1. I must make this single picture freely available to the public.
2. Like above, but also include all parts of my game that somehow interracts with the GPL-picture. For example, if I have code that changes the size/color of the GPL-picture, that code must be made freely available too. Things totally unrelated to the GPL-picture (like my game logotype) can still be kept non-free.
3. I must make every single individual part of my game freely available to the public. All code, all artwork etc.
A big thanks to anyone that can help me!
I'm pretty sure the correct answer is 1.
You have to make that image, and derivatives of that image, available for anyone you give a copy of your software to. They're allowed to redistribute those under the terms of the GPL.
The GPL does not say that you have to give stuff away for free. It just says that you cannot place restrictions on what the person you sell it to is allowed to do with it (the GPL says what they can and cannot do with it; they're allowed to resell or give away for free what they paid you for).
What constitutes a "derivative work" of an art asset in the context of the GPL is not so obvious (the GPL was not designed for art, it was designed for software source code). A direct edit of the image qualifies, screensshots probably do too. A program that loads and processes the image does not (the image is just "data" to the program, the program is not derived from the image). A bundle that includes the images also probably does not (there's some information on bundled stuff in the GPL text, as I recall).
All that said, I'm not a lawyer. Take legal advice on-line with a healthy pinch of salt.
Thanks a lot for a great answer! :)