This wallpaper depicts a rather tired (and cute!) Mizuki Ashiya. I really like this drawing where she actually looks like a female. The art in the later volumes of Hana Kimi doesn't suit my taste, so I'm happy that there was a drawing like this earlier in the manga! I've come to like this wallpaper.
All credit goes to the mangaka Nakajo Hisaya - and one of the many scanlation groups (don't know which one, sorry) for the scans. Please do not use this in any public relations without giving credit to the respective persons.