Wind doesn't seem likely
I'm not sure.
These images are from a crater wall in the southern hemisphere pointing north in the summer, so it gets the full heat (hah) of the Martian summer. You'd expect that to produce a convection of air up over the rim of the crater - opposite to the pattern we're seeing here.
Also, when you put the graphic over a 3D terrain, you don't see any of the tell tale swirls that you normally associate with windblown debris, these lines are going straight downhill:
(long URL approaching)
There's still a chance this could be liquid CO2 seeping out of the permafrost, it would be able to transport material downhill, but it wouldn't leave any tell-tale traces for the orbiter to pick up. But then, liquid CO2 is not normally found in these conditions.
I wonder if ESA can point their Mars Orbiter towards Newton crater any time soon.