That is an odd background for a formal portrait, but I'm sure you are right in supposing that it was made before August of 1902. Perhaps after a fitting? But jewels, gloves, fan and robe do suggest that she wanted to record her look at that stage. The gown would have needed to be altered by August.
I agree that this Board has been a delight, especially during the Swedish wedding! Thanks to all who have posted beautiful photographs and analyzed them.