How to rotate photo
Rotate photo
Select a photo and then the white-framed manipulation handles appear:
Grab the green handle and move it around to rotate the object within 360 degrees.
Or click 
on right panel to rotate photo by 90 degrees anti-clockwise or by 90 degrees clockwise.
You can also use the angle control under Arrange panel on the right to rotate the photo.
Tip
It works out with multiple objects at the same time.