Rotating images is a very simple operation and the Image Metadata Manager makes sure any rotations will be performed with no loss of image quality, and it will also update the orientation metadata information accordingly. Selecting the items 90° Clockwise or 90° Anticlockwise under the Tools / Rotate menu will rotate the selected images by 90 degrees clockwise or anticlockwise respectively and update the orientation information.
For example, if an image has its orientation information as "right way up" and it is rotated 90 degrees clockwise, its new orientation information will show "rotated 90 degrees clockwise", and if the operation is repeated, it will show "upside down". The orientation information can be found at the Shot section of the metadata.
There are two special operations under the Tools / Rotate menu, which are the Auto-rotate item and the Set Orientation to Right Way Up item. The Auto-rotate will perform rotations to the image until its orientation is set to "right way up", which allows the user to correct multiple images at once that were taken with both lanscape and portrait orientations, for instance. To ilustrate I have selected two images, taken from the same place, one in landscape and the other in portrait. When downloaded from the camera, they looked like this:
With both images selected, I have selected the Auto-rotate tool and this is the end result, with both images being correctly upright:
The Set Orientation to Right Way Up must be used only when the orientation metadata information is wrong. The image should be rotated using the 90° rotations to manually put it to its correct position and then this tool can be selected, effectively correcting the image's orientation metadata.