[Roscoe]

You can modify more than one person in a photo (if there is a group) at one time, but only one person at a time.  When you've finished modifying one person in the photograph there's a "Enhance another face in this photo" option in the dropdown menu when you click the "next" button.  If you have many photographs to modify, with one or more people in each photograph, all persons have to be modified individually.  Unfortunately there's no batch function as yet but it has been requested on more than one occasion.  If you think about it, to perform modifications on many photographs à la batch mode would be a daunting task to programme !