I actually almost went that route, @WalterMeiren!
I originally planned to represent the current volume being read. However, there will be a separate thread for volume 2 specifically, which will use the volume 2 cover. Having the same cover page image on both the home thread and the volume thread can be confusing on where to post.
I’d considered using a different series artwork from the mangaka, but the home thread for other multi-volume series threads tend to show the volume one cover. (example, example, example).
Edit: Since the series is only four volumes, I’ve updated the image to incorporate all four. I think that should work for a home thread =D