The MESSENGER spacecraft in orbit around the planet Mercury has been lowering its altitude slowly and as it gets closer to the surface of the planet it stands to reason the pictures should show more detail.
Judging from this image that is exactly what is happening. As MESSENGER enters its last year, the observations will become much more detailed. On 30 April the spacecraft altitide was 199 km (127 miles) and MESSENGER is supposed to get even lower, by about half. There is a orbit-correction manuever set for 17 June.
Those white spots along the crater rim are not washed out areas, they are hallows, depressions with bright centers. Apparently they only occur or are only noticed to occur on the sunlit areas.
Here’s the MESSENGER caption for the image:by