Original code.

SongCell.m

- (viod)loadSongInfo:(LocalSongInfo *)inSongInfo 
{
	// load image 
	if (inSongInfo.source == ... ) {
		self.coverImage.image = [[MediaItem itemWithSongID:...].artwork imageWith...];
	}
	else if (inSongInfo.source == ... ) {
		SongMetadata *metadata = ...
		[metadata getImagWithCallback:...]
	}
	else if (inSongInfo.source == ... ) {
		...	
	}
	else {
		...	
	}
	// update UI
	... 
}