doc is bidding for early warning system for C929 prototype flight testing. I presume that means the first flyable prototype is almost there. Once the prep for the small item is done it will fly. Obviously there may be more than one prototype, and the real thing will come out a bit after all the prototypes. And the real thing itself will need some flight testing. But nevertheless it is very impressive. It shows all the capability is in place, and capable of making a flying plane that size.
The first mid-section fuselage is scheduled for delivery to COMAC by a contractor on or before 2027 September 1st. The rest of the aircraft modules probably need at least another year for delivery. If all goes as planned, the first prototype could appear in 2028.
You are right. These winglets are huge compared to the ones on the older models. I'm not really sure if these models reflect the shape and proportions of the real thing.
In short, I think it is an distortion of the photo. We know that all objects closer looks larger in porpotion than it really is. This effect is further enhanced by wide-angled lens at close shooting point. This photo is certainly taken by a mobile phone and I'd say that all mobile phone's primary camera uses wide-angle lens.