Yeah, the thread can be closed. Per the voting policy, the thread should stay up for a minimum of 7 days. There is also a large majority of opposition votes (11), so we can safely say that this particular image shouldn't replace the current. It's not that it's bad, but that the many votes for infobox changes over the years have led to fantastic art that's hard to improve.
There is another vote thread for another Pink Diamond image going on, though it has to follow the Vote Policy or possibly be closed as well. Encourage PeridotFan64 to fix up their proposal a bit!
I'll get a Discussions Moderator to close this thread. Thanks, guys.