This official art is older but I want to talk about vnc so I don't care. This was the cover of gangan joker in December 2017. The chapter released in December of that year was memoire 23. Seeing as Jeanne didn't appear in memoire 23 this art is instead relevant to the chapters that came before, namely the date chapters, seeing as Jeanne is still wearing her date outfit. This probably relates most significantly to memoire 21 as well considering she hasn't got her hat & parasol and just the general vibes of the room they're in. Interestingly, the spot highlighted on Vani's neck isn't the place Jeanne bit him in that chapter but rather the position of her mark of possession.

There are a lot of blue butterflies in this image. Blue butterflies have previously been used to represent Vanitas himself and/or the paths he could have taken. A good example of this is volume 6's cover where a blue butterfly with frayed wings is shown behind Astolfo. This is obviously because of his similarities to Astolfo and how he very easily could have ended up just like him. Noé even says as much, later down the line in memoire 45.

Looking at the butterflies in the picture with vanijeanne they are swarming around the couple but they all seem to be heading in one direction, towards the painting on the wall. Again, we've seen plenty of blue butterflies before but they've never necessarily been heading to such a clear destination. Below, the butterflies are all heading up and probably to the left as well but there's no visible end goal. The swarm here is more confusing and Vanitas is falling among them. He's got very little control/agency in this piece. It don't want to get too into an interpretation of this one but I think it's probably more generally about him and where his life has been/is being taken, and not necessarily of his own will. Even his expression is quite a bit more distant and sad. Anyway, I just think the contrast between this and the vanijeanne portrait is interesting. Also worth noting that this is Mochijun's twitter header so clearly it's quite a significant drawing.

Back to the painting in the vanijeanne portrait though. The butterflies are heading into the painting on the wall and, interestingly, come to rest on the skull. Correct me if I'm wrong, but I think this is the only official art where we've seen the butterflies alight on anything. If we look at said skull mochijun has very deliberately made one of the teeth pointed so it's a vampire's skull. And considering the chapter this art is referencing I'm willing to bet it's Jeanne's skull. So, if we're assuming the butterflies represent Vanitas and/or his destiny and this skull is Jeanne's that leads to a pretty simple conclusion: Jeanne is going to die.

Which, yeah, isn't exactly a ground breaking revelation. Jeanne has so many death flags it's unreal. But I still think it's cool to see potential foreshadowing in the art. Now, the painting is clearly a vanitas painting: "a symbolic work of art showing the transience of life, the futility of pleasure, and the certainty of death" popular in the 16th and 17th centuries. There's some pretty common symbols used in this piece: money  an hourglass, flowers, a book, even the butterflies. All are expected symbols. The flowers are perhaps most worth looking at.

One is a lily, they can represent a number of things but probably most relevant here is the soul of the departed. They're also commonly associated with funerals. Behind the hourglass is a pink flower and I'll be real I haven't a clue what it is so I'm not even going to touch on it. I think the purple flowers are balloon flowers. These can apparently symbolise friendship, endless love and honesty. I think endless love and honesty are the most interesting for the couple that is vanijeanne. At this point in the story (pre-gévaudan) they didn't love each other but the love part could have been foreshadowing of their current relationship. Honesty could relate to the promise Vanitas made Jeanne. I wonder then if he really will kill her and if indeed that will be seen as an act of love? Or instead the honesty could be seen as ironic if, rather, a tragedy befalls them and Vanitas finds himself unable to keep his promise.

Now, I think the cracks in the skull are fascinating. If we assume this is Jeanne's skull it may foreshadow how she dies. There are two thin cracks coming from the eye sockets, the balloon flowers blooming from the larger one above the left eye. I'm not sure what type of injury would cause such a thing but since I've already started speculating wildly I may as well say it looks more like damage a vampire would inflict rather than Vanitas himself. Also, interesting that it's connected to the eyes at all considering their importance for vampires.

Final thing, there's what looks to be a crack at Jeanne’s waist. It could also maybe be a cobweb, potentially representing ensnaring the butterflies/Vanitas but I prefer a crack as the interpretation. I'd considered that maybe the whole art was supposed to be viewed as something reflected in a mirror and that's why there's a crack but looking at Vanitas's earring and the side of his neck the mark is on this isn't a reflection. I think it's possible that like the skull this could be foreshadowing of some future injury Jeanne will sustain or of how she dies. It just seems an odd detail to add if it has no significance.

Anyway, I'm done here. Sorry for the unhinged rambling. Feel free to tell me your thoughts if you have any. This is just interpretation/speculation for fun so uh don't take it too seriously. I'm well aware that I could be reaching or misinterpreting or just plain wrong.