Winter Woods

What's the difference between an illustration and a painting? I've puzzled over that question through the years. Is it a matter of style? If it tells a story, does that make it less of a painting? What if it merely suggests a story? Weren't almost all of the Medieval and Renaissance paintings illustrating some kind of story? And what does it really matter, in the end? It's an image, and the viewer responds. I really just wanted to paint an owl. And the woods came from my imagination. What is the story behind it? I'll never tell...