Вот в этой книге по вашей ссылке под тем самым изображением написано:
These nine figures and one fragment from Iran
are believed to derive from a royal context. 1
As suggested by their iconography — jeweled
headdresses, arms, rich vestments — and by
similar images found in situ, they were proba-
bly meant to decorate the walls of the recep-
tion areas of palatine complexes, where they
typically flanked or faced the enthronement
area.
Там нет уверенности в этих словах.