Re: Hard to tell without repeat imaging . . .
Could be frost/snow.
Could also be a lava flow. It appears to have filled cavities ahead of it, but that's also where frost would be expected to accumulate.
Hard sayin'.
In the main pic, though, there appears to a fault line cutting through the middle of the large crater near the bottom. It runs diagonally, giving the rendition of two white half circles to the right where it bisects two smaller craters.
Lot of underlying craters.
How's it goin'?
Dan