I still think that silvery outfit Jadis appears to be wearing is being worn for CGI purposes, mainly, and may not be the actual one that she appears in, when the film is complete. I'm sure that the silvery boots and tunic are mainly for reflectiveness.

Posted by: @impending-doom

My worry with this change is that, in the book, this is when Digory first overhears the 'land of youth' conversation with Aunt Letty. That moment is foundational to the entire thrust of the second half of the story…

If they’re adding what looks like an action sequence here, I hope it’s still framed in such a way that the audience comes away with the same concern Digory has in the book which is his desperate hope for his mother. 

Yes! That is a real concern.

I think they could probably move the ‘land of youth’ conversation earlier in the story - possibly before the introduction of the rings.

(The more I think about it, the less I like the idea, this is not a direction I hope the film goes in. Nonetheless, a search for a cure for Digory s mother could be used as Digory’s motive for visiting other worlds when Digory and Polly first realize the nature of the wood between the worlds. It could also be used to justify why he awakes Jadis [if he thinks she could help his mother]. It could even justify why Digory doesn’t use his yellow ring when riding on the horse with Jadis [because he thinks this woman will help his mother and hence is conflicted whether he wants to stop her]. This would change the story WAY too much for me - very green mysty - but it would keep Digory and his mother central in the viewer's mind throughout.)