Rotate the picture by increments of 15 degrees by holding ⇧ Shift while rotating.

Rotating the image to a precise orientation will be harder to accomplish with the mouse. If you need to orient your picture to an exact degree, read the method about rotating your picture by degrees.

If you have trouble finding the Rotate icon, hover over each icon in the Arrange group to reveal a text box explaining what the icon is.

Flip Vertical will essentially mirror the image along the X-axis. Flip Horizontal will essentially mirror the image along the Y-axis.

Any degree greater than 360 degrees will be unnecessary since rotating the picture 360 degrees will only return the picture back to its original orientation. Press OK when you are done to apply the rotation.

X-Rotation will rotate the image up and down, as if your were flipping an image away from you. Y-Rotation will rotate the image side to side, as if you were turning an image over. Z-Rotation will rotate the image clockwise, as if you were moving an image around on a table.