How to comply with sharealike clause when using creative commons cc-by-sa licensed images in commercial work?
If I want to use images licensed under the creative commons cc-by-sa license, how do I have to share the derivative work in order to comply with the license of the original image?
In particular, how is sharealike compatible with commercial use?
If I use cc-by-sa images in a design that I want to print on a shirt and sell, it seems like that should be acceptable because the license does not prohibit commercial use -- However, how would I have to share the work? Is my design considered the only derivative work in this case, or would I have to consider that in printing a shirt, a new work is created which also must be licensed under the same license? If so, does this mean that the shirt cannot be sold?
I'm not a lawyer, but there are a few things here that any designer who's worked with CC material can clear up.
does this mean that the shirt cannot be sold?
Not at all. Plenty of people sell physical goods containing open-licensed intellectual property (e.g. open source software on a disc for convenience or installed as a service, books that are out of copyright...).
The key thing is, you can sell your shirt, but you can't stop others printing and selling the same design.
The licence also stops other people using your design and trying to stop you using it (this is what these sort of licences were created for, and why they're better than no licence).
It applies to the intellectual property of the design. If you've bought some shirts and some ink, and printed a CC design on them, those shirts are still your property, so you can sell them.
You just can't stop other people copying you.