initWithContentsOfFile path    UIScreen instancesRespondToSelectorscale  UIScreen mainScreen scale   	         path2x  path stringByDeletingLastPathComponent                            stringByAppendingPathComponent stringWithFormat,                                                            path lastPathComponent stringByDeletingPathExtension,                                                            path pathExtension;           defaultManager fileExistsAtPathpath2x  super initWithContentsOfFilepath2x;          super initWithContentsOfFilepath;