Proprietary resources in GPLv3 project

Question

Can a GPL project use proprietary resources (icons) as part of it? What I mean is that if it is possible that there is a repository covered by a GPL license that has a build script that downloads resources from another repo (and these resources are covered by non-OSS license - permission for private use without redistribution rights).

There would be an official distribution (build) of software using icons with permission for private use without redistribution license, but one could build their own fork or build of software, but would have to use their own image resources.

Is a concept like this compatible with GPLv3 or would this not work out?

The thing is that the software is rich with icons that I paid a designer to make and I would like to distribute the software in OSS means, but keep these icons in my ownership (and distribute my build with these icons only).

I know one needs to provide full build script and build instructions with GPLv3 software, so the question is if not offering icons would break this rule?

Answer 1

There would be an official distribution (build) of software using icons with permission for private use without redistribution license, but one could build their own fork or build of software, but would have to use their own image resources.

Is a concept like this compatible with GPLv3 or would this not work out?

As the icons and the software are most likely two independent works as far as copyright goes, this is compatible with the GPL, but I would still advise against a "no redistribution allowed" license on the icons, as it is too easy to accidentally infringe upon.

As an example, suppose I download the official build of the software and then provide it to my friends as well. That is redistribution of both the software and the icons and would thus infringe upon the license of the icons.

As an alternative, I would use trademark protection on the icons. Redistribution with the original software would be allowed, but any other use of the icons (in a modified software or in a completely different context) would not.

Answer 2

Yes, such thing is possible - how exactly depends on a few conditions:

If you are the sole owner of copyright, you can do as you want anyway and you need to exercise little care on how you bundle and ship code and ressources (icons).

If the code is GPL-covered and other authors also have copyright, it is good and established practise to separate code and ressources so that they can - at least in theory - be distributed separately. Then it is easy to indicate that the source code for the programme falls under license X and the ressources are governed by another license Y, and both can be indicated easily inside the programme to the user and in a readme / license (possibly one for each).

As an example, OpenTTD is an open source rewrite of the copyright-protected Transport Tycoon Deluxe. Users can use the original paid-for graphics, and the installer also allows to make the available to the game, if you point it to where they are found. Alternatively it allows to install free graphics; internally the graphics are treated as a required dependency where you have to choose one option during install in order to get the game going.

Answer 3

I would suggest designing the software so as to allow a user to supply a set of icons, and include with it a set of functional (but not necessarily attractive) icons that you would allow to be freely distributable under GPL, and bundle it with an alternate set of icons which is explicitly not part of the GPL-licensed package, but which users may load into it. I think the GPL would require that the open-sourced parts of the package be adequate to build a working application, but supplying a freely distributable set of functional icons would meet that requirement even if icons that are distributed under a more restrictive license would make the program nicer.