Sometimes You Must Meet to Understand Gintama : Season 3 Episode 28

Even though it’s believed the letters are coming from Okita, Shinpachi's response letter turn out to be a big hit. Urara is happy her older sister has received a response to her letters. But her older sister confesses that she sent Urara's picture with the letter. And it looks like both Shinpachi and Urara sent someone else's pictures with their letters!