I have gotten help from FSF licensing and they suggest using the GPLv3 to license the art as well as the code. After asking this question:

i'm a volunteer for a non-profit organization and am helping them develop a free open source Android app that i hope will be licensed under GPLv3

We are going to use the logo and some other graphics files from the organization and are wanting to use licensing of this artistic work to protect ourselves from anyone doing damage to the reputation of the organization

What license would you suggest us using for our artistic work and also the code itself? (Any thoughts more in general about what we can do to protect the organization?)

I got this response back:

GPLv3 is an excellent choice here for both the code and the art. Section 7 of GPLv3 permits that your organization place additional terms which will help protect the work:

Section 7.b allows your organization to add terms "... Requiring preservation of specified reasonable legal notices or author attributions in that material or in the Appropriate Legal Notices displayed by works containing it ..."

Section 7.c allows your organization to add terms "... Prohibiting misrepresentation of the origin of that material, or requiring that modified versions of such material be marked in reasonable ways as different from the original version ..."

Section 7.d allows your organization to add terms "... Limiting the use for publicity purposes of names of licensors or authors of the material ..."

And section 7.e allows your organization to add terms "... Declining to grant rights under trademark law for use of some trade names, trademarks, or service marks ..."

I hope this is of help. Please feel free to write back with further questions.

I'm grateful for the service that they provide at the FSF (Free Software Foundation) and i hope me posting this help someone else too

I have gotten help from FSF licensing and they suggest using the GPLv3 to license the art as well as the code. 

After asking this question:

i'm a volunteer for a non-profit organization and am helping them develop a free open source Android app that i hope will be licensed under GPLv3

We are going to use the logo and some other graphics files from the organization and are wanting to use licensing of this artistic work to protect ourselves from anyone doing damage to the reputation of the organization

What license would you suggest us using for our artistic work and also the code itself? (Any thoughts more in general about what we can do to protect the organization?)

I got this response back:

GPLv3 is an excellent choice here for both the code and the art. Section 7 of GPLv3 permits that your organization place additional terms which will help protect the work:

Section 7.b allows your organization to add terms "... Requiring preservation of specified reasonable legal notices or author attributions in that material or in the Appropriate Legal Notices displayed by works containing it ..."

Section 7.c allows your organization to add terms "... Prohibiting misrepresentation of the origin of that material, or requiring that modified versions of such material be marked in reasonable ways as different from the original version ..."

Section 7.d allows your organization to add terms "... Limiting the use for publicity purposes of names of licensors or authors of the material ..."

And section 7.e allows your organization to add terms "... Declining to grant rights under trademark law for use of some trade names, trademarks, or service marks ..."

I hope this is of help. Please feel free to write back with further questions.

I'm grateful for the service that they provide at the FSF (Free Software Foundation) and i hope me posting this help someone else too