When you use the View, Rotate commands, the on-screen display of the image is rotated. To permanently rotate the image data, you must use the Raster, Rotate commands.
To rotate the active raster image:
1. Choose Raster ® Rotate.
2. Choose the rotation to apply to the image: 90 CCW, 90 CW, 180, Portrait, or Landscape.
A progress indicator appears as the image is rotated. The new image's header rotation value is 0.