Honestly it is sort of vague-looking. It is basically dark Rey but with white eyes like Palpatine’s. And I think she is sitting on the dark throne but I think it is a midshot. Plus, it is literally a quick flash, basically a few frames.
To me it looks like it was Frankensteined together in post rather than shot with that intention. Plus, it is only Rey, and not Rey and Kylo together, as they described the vision in the film.