If the image you want to include is not on Commons, then we have potential issues.  You say you have the band's permission, but of course we have no way of verifying that. I don't doubt you, but legally Wikipedia needs to be certain.  I'd have to get back to you if that were the case.  It may be easiest to try including the image, and very shortly I'd expect it then to be challeneged or removed.  But at least at that time you would have full standard instructions on how to proceed. Hope this helps,