Click "Keys" under the "Player" section on the left-hand side. This displays a list of all the key commands on the right-hand side. Key commands are a combination of key-presses that perform a task in the player.
Scroll through the key commands until you see the "PnS Rotate" commands. These commands are what are used to rotate your image. The "X, Y and Z" after "Rotate" distinguishes which axis is rotated. When viewing an image that needs rotating, press the corresponding key listed next to the "PnS Rotate" command you need. For example, if your video image were upside-down you would use the "PnS Rotate Y" command.