Of course the Moon is exactly the right size in that picture. You just have to be at the right distance... and some zoom, possibly.
Example: take a tennis ball and a football. Place the football onto ground or floor so that you can see it. Then take the tennis ball into your hand and keep it between your eyes and the football. At some point, the tennis ball's apparent diameter equals the one of the football. Closer, and it appears bigger; farther, and it appears smaller.