You sure thats Ritsu? I mean the hairstyle is the same, but the breasts are way too large and she doesnt seem very Ritsu'ish, if you know what I mean :/

It's a promotional shot from the artist's new doujin/eromanga, 「下着ドロボウにご用心？」, apparently. Maybe it's about Ritsu, but I doubt it.

Thanks to the info on the title, I was able to sniff out some more info. It's part of the Comic Mujin April 2009 anthology, and it's not Ritsu. Rather, she's some big-busted girl named Akane.

Thus, I'll be removing the tags related to Ritsu.