It's no wonder the final book in the Harry Potter series, Harry Potter and the Deathly Hallows, was broken up into two movies. Aside from obvious financial incentive, the book weighed in at a hefty 784 pages, handily doubling the length of the series opener and then some. It seems JK Rowling had a harder time editing her writing as the books went on; some other people, however, have no qualms whatsoever with paring it down.
Artist Lucy Knisley recently created an infographic called The SummHarry, which traces the complete journey of the precocious wizard in one chart. All seven novels are accounted for in the largely wordless depiction of the series that helped make JK Rowling a billionaire. Knisley shrewdly chooses only the essential moments to choose, without cramming any more visual information in them than need be. She even inserts some of her own humor into the proceedings, captioning the introduction of the villainous Dolores Umbridge as Defense Against the Dark Arts Professor at Hogwarts with Dumbledore saying, "Another fine hire by me."
Fair warning for anyone wanting to use the chart as crib notes: you might need some sort of adaptation spell to understand what is happening in this chart without having read the books before.