This picture raises a lot of questions. The picture taken is mostly likely from Aya, seeing how no one seems to paying the person taking the picture any mind. I’d question what Cirno is doing to Komachi in the background, but it looks like she’s stealing sake. As for what Nitori is doing hidden there, that’s another question.
Some people will ask why does Rinnosuke have his shirt off. It’s a mystery really, unless you want to just call him Mannosuke and then call it a day. Alice looks drunk, being a lot more assertive as we see her groping Marisa’s chest. It looks like everyone is having a good time, you don’t see Reimu that happy this often as the three fairies dig into the food themselves. Now about that Yukkuri Marisa… in the background. This is how Gensokyo should be though, with more people around and everyone happy. After a few rounds of danmaku afterwards. Oh, how I wish I could join that scene.