In Ranma's own words:

"So just about every single Sakura Matsuri, I run into my sister Crissy.  She usually wears a kimono, Priestess Rei Hino, or something appropriate for the event.  When I run into her, I end up taking a few pictures for her website, Sailor Moon Avatars.  But this time, now that I have my new camera and she was with a few mutual friends of mine, I decided to snap photos of us for today."