We've seen the J-10C carrying the KD-88 ASM as well.
The absence of images of J-16 carrying full air-to-ground load has led me to believe that it is not intended to be a dedicated strike fighter like the F-15E. It will probably fulfill a similar role as the Su-30s in the former VVS -- long range interception and air superiority.
I don't think that's very sensible, because as many others have written, we've seen J-16 prototypes flying with various other A2G munitions, presumably being integrated with those weapons.
I would suggest that pictures of J-16s carrying various loadouts -- and in fact, for all PLA fighter aircraft -- is carefully released, and that just because we do not see a certain loadout being photographed does not mean various loadouts or various munitions are not in service.
For example, we have yet to see any PLA flanker carrying a "full" air to air loadout in the air, but that doesn't mean they cannot. Chances are it just means that carrying such loadouts are a rare occurrence, plus that when such loadouts are carried they probably don't take photos of it for release.