You can rotate the image 90┬░ clockwise or counter-clockwise, or rotate it 180┬░, by using the rotation commands on the Transform submenu of the Image menu. These commands can be used to change between Portrait and Landscape orientation. They work on the whole image. If you want to rotate the image at a different angle, rotate a selection or rotate a layer, use the Rotate Tool. You can also rotate a layer by using the Layer Transform menu.