To rotate photos, you must be logged in. From the Tools Menu, choose Rotate.
You'll see the following:
Simply click each photo you want to rotate. They will be highlighted in red.
Then choose the direction you would like to rotate them — Left, Right, 180 or Mirror — and click the Rotate! button.
Rotation will occur in the background and may take several minutes. In the meantime, you can continue to use SmugMug. As you browse your gallery or click refresh while viewing it, your newly rotated photos will gradually replace those that are currently there.