I am not sure if the He 177 was ever used for dive bombing. It was in the design specs to be able to do so, yes. Because of the primitive bomb sights in existance at the time (before the war), the LW had a preference for dive bombing capability, to be able to bomb with accuracy.
By the time WW2 started, bombsights had improved a lot, a dive bombing, even though still accurate, was no longer needed. Does anybody know if the He 177 was fitted with some sort of dive bombing sights..?
BTW, the picture you have shows a Greif with a Henschel-made, remote controlled glider bomb, that's why it's on external rack.