Apparently this picture was posted after the stream where he accidentally called her his girlfriend (that's what the "oh well..." is referring to).
I guess that does imply they're more than friends, but I don't know how that works if she's aro/ace. I'm just confused about this whole situation.
There is no confusion. They're in some sort of committed relationship. Everything that is known about human sexuality is that it's fluid. People change and grow and evolve. Especially our generation.