I am loathe to speculate on raw images... BUT here goes
look at the bottom panel of this triplet:
If IF the dark areas are liquid then the distribution of the white objects (hypothetically solid) is very remeniscent of Icebergs calving off of a glacier into the 'ocean'...
same here:
This would indicate active movement of the surface and a mechanism for the rapid resurfacing indicated by the lack of visible craters...
just my 2 cents (and no I am not a planetologist, nor do I pretend to play one on the web...)