I was thinking about drawing all the characters, but I got too lazy. I did them, kind of posing for a photo, with no background, of course. I'm terrible at it. Backgrounds, I mean.
Anyway, "say cake!" refers to a prank of Mizuki's family (Mieko's family). It's because when Mieko was a child, and heard the word "cake" she smiled automatically. So everytime her parents wanted to take a picture of her, they screamed "say cake", and then, there were a little child smiling.