1. A method for generating and manipulating grouped photos, executed by a processing unit, comprising: selecting a plurality of photos shot in a geometric region from a storage unit; reading a plurality of shooting dates of the photos; calculating a plurality of time intervals between every two adjacent shooting dates; generating a plurality of CDFGs (Continuous Data-time Fragment Groupings) according to the time intervals; for each CDFG comprising two or more shooting dates, obtaining a total number of photos associated with each shooting date; for each CDFG having two or more shooting dates, generating one or more groups according to the total numbers; and displaying information regarding the groups in a map displayed on a display unit: wherein the step for generating a plurality of CDFGs comprises: calculating a first median of the time intervals; and merging the two adjacent shooting dates with a time interval being less than the first median in sequence to form the CDFGs.