1. A computer-implemented method comprising: extracting facial features of a collection of digital photos; clustering the collection of digital photos into a plurality of face groups, at least first and second face groups of the plurality of face groups each including multiple digital photos, each photo having a facial feature satisfying a programmed facial similarity requirement; associating an annotation with the at least first face group; adding the second face group to the first face group; and responsive to the adding, automatically associating the second face group with an annotation of the first face group.
1. A computer-implemented method comprising: extracting facial features of a collection of digital photos; clustering the collection of digital photos into a plurality of face groups, at least first and second face groups of the plurality of face groups each including multiple digital photos, each photo having a facial feature satisfying a programmed facial similarity requirement; associating an annotation with the at least first face group; adding the second face group to the first face group; and responsive to the adding, automatically associating the second face group with an annotation of the first face group. 10. The method as recited in claim 1 , further comprising: allowing a user to select a target face group from the plurality of face groups; ranking the plurality of face groups according to face similarity of each face group to the target face group; and displaying the plurality of face groups according to a result of the ranking.