My son and I have been reading nightly since he was born. I read the entire Harry Potter series out loud (that equals the first five books at that point) during his first year of life. While he does not remember this experience, I do.
For the last couple nights I have reintroduced chapter books to our repertoire with a book called Lucy on the Loose. It's about a beagle. My son is into dogs. What can I say? But I'm learning a lot about how stories are structured because the plot/subplot elements are pretty darned straight forward. Chapter One: Intro of devious cat that will tempt Lucy the Beagle away from loving owner. Chapter Two: Intro of loving owner's (Bobby's) shyness and love of superheros (including Superman and the Lone Ranger). Chapter Three: Lucy the Beagle cuts loose.
What's my point? I can pretty much tell you right now that the only way to get Lucy the Beagle back is for Bobby to overcome his shyness and then he will become the superhero of his own life. I don't know exactly how all that will come into play but it's part of the inevitability that should be there in every novel, be it for children or adults. It's just easier to see in children's books...especially those really-really beginning reader books.
The first pleasure of this whole thing is that, as a writer, I get to see the plot/subplot structure and it gets me thinking about how I'll utilize it in my own writing. The second pleasure is that my son knows none of this and is just enjoying the story.
Even without the pictures.