Copyright != Licensing != Trademark usage
Thank you very much. I want to prove my understanding:if we just declare and use some picture as our logo it identifies the project even if the picture is licensed as e.g. CC3+ by-sa and can be used by other people for all purposes not related to their identity.
Correct? If it is true I would ask the artist to release his work under the CC license, and I would would even have a good argument for doing so because all distributions of this picture were also a kind of project advertisement.
Regards, Dimitry