Why is it so large? Is it the same model used to create 3D effects on iOS lockscreen?

I think it's essentially a transformer, so it just stores a bunch of weights. As a model that's supposed to be able to convert any image to 3d scene, it's pretty nice size actually.

Regarding the ios lockscreen - I believe they are different models. I think Apple use this one to generate those Vision Pro 3d photos though, but I'm not too sure.

No the 3D effects are much more simple for the lock screen…more akin to old-school animation via layers