Adding to what Claes wrote - the pictures were taken in June 1905, when Crown Prince Gustaf (later King Gustaf V) and Crown Princess Victoria attended the wedding of their son Prince Gustaf Adolf to Princess Margaret of Connaught. I believe the pictures show the royals dressed for the wedding itself (an afternoon tiara and uniform affair), though there were gala banquets on several days, so it could be from a photo-session on another day. The King of Sweden at the time was their father/grandfather King Oscar, who did not travel to the UK for the event. Also attending the wedding from Sweden was Prince Wilhelm of Sweden (a younger brother of the groom), who is pictured.
Beth: Queen Victoria of Sweden never pierced her ears, and thus did not wear many of the earrings from the familiar parures.