If the photo you posted is a real photo of Heather Heyer on the day of the incident, then I believe she was definitely struck by the car -- and I believe I can identify her in the photo below, too:
1. Look over to the right side of the photo and find the shattered side mirror of the Toyota Tundra pickup truck.
2. Go straight up to the guy with the idiotic tattoo, flying upside down in the air.
3. Directly beneath his left knee you can see the head and neck of what appears to be a heavy-set person wearing a dark-colored top. I've seen a couple of unconfirmed posts on various sites claiming that this is Heyer.
4. The angle of her head and position of her torso beyond the flying dude clearly seem to indicate that she has been knocked off her feet.
Good catch. I could find no other pictures showing the accident from the front. In your photo, she seems to be wearing a dark choker of some kind, which she was not wearing in the earlier photos. But that could just be a shadow, or something she put on later.
I know this is cold-bloodied, but that photograph is really cool.