Who do you consider to be the author/creator?

It can depend on the work. Kingdom Come, The Killing Joke, Watchmen and All-Star Superman for example are all works that depend as much on the illustrator's contributions to the overall story as they do on the writer's. In those examples Ross, Bolland, Gibbons and Quitely were involved right from the start in the creation of the story, and their art and layout not only illustrates the writers' words but shows aspects of the overall narrative that the writers words can't. Alan Moore has always been especially aware of that and has made it clear to his illustrators that the work is as much theirs as his; and in addition to their input at the beginning, if they later see a way to improve on what he's described he encourages them to do it. Watchmen and The Killing Joke are especially good examples of that.





All for a box of chocolates...

It all depends upon who is paying whom. The author is the one who does the paying (and borrowing, so investors don't count). A graphics artist might hire somebody to write a story. In such a case the graphics artist (sketcher/doodler/painter/sculptor/modeler) is the author. A storyteller might hire somebody to draw illustrations. In such a case the storyteller (novelist/historian/journalist/chronicler/preacher/dreamer) is the author. Sometimes neither one is the author. Sometimes both are equally the authors.