This error may happen when you try to load
UIImage and your asset string is
nil. For now this will not crash your app but may case some future problems. This may also lead to some UI inconsistency. To track down issue like this we need to set symbolic breakpoint:
$arg3 == nil condition (on Simulator) or
$r0 == nil condition on iPhone device. This will stop executing your app exactly in the line where you try to load broken image.