Image structure, 180, 190, 191, 192, 223, 224, 224-225, 225, 353
  bit-plane organization, 227
  calculation of data size, 226
  color computation, 228
  Depth, 226, 231
  Height, 226, 231
  ImageData, 226, 227, 231
  LeftEdge, 226, 240
  NextImage, 226
  PlaneOnOff, 226, 230-231
  PlanePick, 226, 230
  TopEdge, 226, 240
  Width, 226, 231