C.S Lewis' Imagination

I was just amazed after reading It All Began With a Picture because I can imagine Lewis looking at the picture of a Faun carrying an umbrella and parcels in a snowy wood,and saying to himself, "Uh... I could make a story out of this." So that one picture that he saw made him to have an epic idea to write an awesome children's book that made history. C.S Lewis and J.R.R Tolkien discuss with each other of how they should write their stories with a christian allegory. I realize that not only the characters of The Lion, the Witch and the Wardrobe has christian symbols, but the weather as well. I learned that winter means death and spring means new beginning. In the beginning Narnia was winter, and since winter was death I thought that symbolize as sin. The queen was taking over Narnia so everything was dark and gloomy. But when Aslan died and rose again, even before that, it was spring because it was a new beginning of the story. I love how Lewis comes up with ideas to write a story than just "make things up" along the way.