In Catching Fire, in chapter 17, after Peeta goes to his private session with the Gamemakers, he tells Katniss and the others that he painted Rue:
"Actually, I painted a picture of Rue," Peeta says. "How she looked after Katniss had covered her in flowers."
But I realized: how does he know what Rue looked like after Katniss covered her in flowers? It was clearly stated that what Katniss had done was a sign of rebellion so they omitted it when they recapped the hunger games after they won. She had said:
"It's like watching complete strangers in another Hunger Games. But I do notice they omit the part where I covered her in flowers. Right. Because even that smacks of rebellion."
I figure Katniss told him about it and he used his imagination to draw her, but he clearly said he painted what she looked like, which makes it seem like he actually saw it. Only, there was no way that he could've seen it. The only time Katniss was sure that they would air it on T.V was when they picked up Rue's body from the arena, so he couldn't have seen it then. And he couldn't have seen it later either because it wouldn't make sense to show it again if they clearly omitted it the first time they recapped the games. I also don't think Katniss would have described it to him since remembering Rue's death would've been hard for her. So how did Peeta know what Rue looked like covered in flowers?