I pictured a big booth with candles too...nothing fancy though. Also, that other picture when they're in the cafeteria, I thought they were sitting at long tables, not little circular ones. I guess this is what happens when you read the books before the movies (which my mom has made me do since the first Harry Potter book/movie.
) At least it's better than the alternative, which is when you picture the scene the same as the movie. My friend read the book after a bunch of pictures came out, and she could only see the characters that way.