Bestselling writers know that image counts according to The Guardian and they make a few good points about the importance of vivid imagery. While I agree it helps to have a character that is physically distinctive, it shouldn’t replace of the construction of what should be a well-rounded character from the start. Image is a lot, but it is not everything.
Robert Langdon for me is a case in point here. I don’t think he is a particularly strongly illustrated character; cheaply drawn as far as I am concerned and I wasn’t surprised when they went for the lazy choice of Tom Hanks to play him. The only thing I remember about his physical description is the Mickey Mouse watch. I never understood it but at least it did its job because Langdon sticks in the mind. He is otherwise portrayed as a maverick academic, arguably a stock character in the first place. The watch sets him apart from the rest.
Harry Potter is distinctive for his glasses and for that scar on his forehead (the scar is a major plot point, the glasses are not). He stands out as a literary character, he is identifiable even to those who have not read the books or seen the film and have no interest in doing so.
I use those two characters above as a contrast. Harry Potter is a well-constructed character who grows, learns and blossoms through his seven years at Hogwarts. We watch him go from wide-eyed child who does not yet fully comprehend the burden he is about to be put under, to brave yet sometimes reluctant hero. By this time, his physical appearance becomes irrelevant anyway. Dan Brown makes reference to the Mickey Mouse watch in all four of the books I have read. At no point does it become part of his character, it is there merely as a quirk. But… as the article states, was this a deliberate quirk, a deliberate attempt to “look wrong like the classic crime fighters”? Was it a tool to demonstrate that wrongness? It is possible but I’m not sure that Brown really gave his character that much thought, the idea of presenting him as a modern Sherlock Holmes or Marple I find as much amusing as in poor taste.
Good characters certainly need a visually striking image but that should never come at the cost of a well-developed and interesting characterisation that will surprise the reader and have them pondering on his or her finer points for years to come.