a. In the photo you see her with Dave standing on a rock.

b. In the photo you see her**,** with Dave standing on a rock.

c. In the photo you see her**,** with Dave**,** standing on a rock.

In which case is this conclusion correct:

1.She is standing on a rock.

In which case is this conclusion correct:

2.Dave is standing on a rock.

And in which case is this conclusion correct:

3.They are both standing on a rock.