The iTunesArtwork and iTunesArtwork@2x graphics are needed only for development and AdHoc builds. They serve no purpose in production/AppStore builds and should be removed before you build & submit your app to the iTunes App Store. (Otherwise they're just making the IPA bigger.) See https://developer.apple.com/library/iOs/qa/qa1686/_index.html for a reference on that. The Titans and I tested with an app published without those files and the icon still appears in the iTunes desktop app (for syncing).
We should update the build scripts to omit these files from AppStore production builds.