*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Only RGBA or White color spaces are supported in this situation.'

在幫一支app升級iOS 9以及Facebook SDK 4.6的時候

出現了錯誤訊息

其中包含了

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Only RGBA or White color spaces are supported in this situation.'

發現原來是

[[UINavigationBar appearance] setBarTintColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"bar_background.png"]]];

這行的原因