Some of the CC licenses define ShareAlike term:
ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.
http://creativecommons.org/licenses/by-sa/3.0/deed.en
What does it mean to "build upon"? If image licensed under ShareAlike term becomes a part of some software, does it mean that software was built upon the image and it must become CC? Is it just a graphics on screen that is built upon image? Or is image considered a separate part on its own rights, with software being a medium mentioned by Share term:
Share — copy and redistribute the material in any medium or format
So that it can be used without affecting the software license.