Plugin Birthdate gives people age on each photo. Since Piwigo knows the date of the photo and if you tag the photo with people name, Piwigo only needs to know the people birthdate to display their age on photo. Plugin Birthdate let you define the birthdate of any tag.
Depending on the age, Piwigo will display seconds or minutes or hours… or years. If you have a family photo gallery, you will certainly appreciate to immediately know the age of kids on each photo!