
Emi's drawing is inaccurate. It's sad, but she does not have legs. While Rin's and Lily's image shows their disability, Hanako's and Shizune's don't (well unless you play the VN it becomes obvious). Also, their background is kinda dark, IMO. Makes me think that drugs are what caused them to be this way.
she has two sets of legs (one for her running and another for outings) plus a wheelchair if you go through her story arc, otherwise she'll be on her running legs through out the game when you see her.