The garment seoras was wearing was very like a frock but whereas on a girl it would be open at the bottom hem, for a boy it would be elasticated all round and buttoned between the legs so pouching over.The fabrics were a little different for boys too and he yokes were embroidered with ducks and trains etc but girls dresses were embroidered with flowers ,fairies etc.You could tell the difference!
They usually were smocked at the chest to take in the fullness, and set into a yoke. They were the devil to iron , especially those made of rayon or cotton before the days of drip dry and non iron fabrics .
Seoras is convinced he was put into a frock for that photo.Bless him. Viktoria.