These two images are excerpted from the same HiRise product, which I found on page 56 of 62 for the "science theme" of "Aeolian processes". In the large image below, excerpted from the original product at full resolution as indicated by the white rectangle, you can see smaller scale ripples on its surface. From the product information, I think the ripples are a meter or two across, and the excerpted scene is 250 meters wide.
