Symbolism, Imagery, Allegory
Remember that painting of the house in Asland? The one that all the girls (including Miri) went totally gaga over when Tutor Olana announced that it would be given to the new princess's family? Well it turns out that the painting doesn't accurately represent the riches that await the girl who becomes princess—the promise of the house is actually a lie. But in the end it doesn't even matter, because Miri's family didn't actually want the big house; they were just as happy with having Miri home and receiving that beautiful painting as a gift.
Marda and Pa were back from the quarry early and sitting on the large stones beside Britta's garden. Miri gave them the painting, leaned her head against her pa's shoulder, and smiled as they cooed over the gift. (25.161)
In this way, the painting signifies those things that Miri thinks she wants, but finds out aren't real or right for her after all. When she goes to the academy, she thinks that she might want to be the princess so that she can provide these fancy things for her family; by the end, however, she discovers that her family just wants her home and that she doesn't want to marry the prince at all. Similarly, even though Miri has wanted to work in the quarries her whole life, by the end she knows that it's not the place for her.