Let’s talk about Elsa’s magic here. Ability to create ice and snow? Check. Immunity to cold? Check. Able to create sentient life? Check. So powerful she accidentally freezes an entire kingdom and doesn’t even need to consciously maintain it? Check.
Now, how about this: does Elsa destroy matter and replace it with ice, or does she convert normal matter to an icy replacement?
Check out the dress. That high-collared coronation dress had no exposed front but her ice dress does, and we see the top of her chest and collar bone. In addition, she has completely new shoes (with heels instead of flats) and a noticeable lack of leggings/stockings. What happened to those?
Now, look at Anna’s boots. You would think it’d be simple to add the skate blades onto the soles of the boots and encase the heel for support. Instead, the heel completely disappears, replaced by blades of ice.
Destruction or conversion? The evidence can go either way. Personally, I lean towards conversion. Perhaps this is a way that some of Elsa’s ice creations can survive in the heat of summer without her concentrating on them.