Alan Moore once commented that his (epoch-shattering) comic Watchmen could never be adequately adapted into a movie because it relied so heavily on the actual sequential art form to tell its story. Perhaps because movie storyboards are done in panel form or because strips of comic panels bear a surface resemblance to film strips, comics have often been considered a sort of movie on paper, visual storytelling that was ready-made for easy translation to the screen.
The truth is the form is full of its own visual language, and expresses itself in ways that film simply can't encompass (though, of course, film is full of its own intricacies that can no more easily be adapted into comics form). The misinterpretation has something to do with seeing the comic as its parts rather than the sum of them. Taking the entire work as an artistic whole, however, exemplifies some of the form's artistic possibilities. Mr. Moore and artist Dave Gibboms, for instance, took the second half of Watchmen 5 (Chapter Five in graphic novel form) and turned it into an exact compositional reflection of the first half, creating a perfectly symmetrical comic book (the issue's title? "Fearful Symmetry.")
The next time you pick up a comic or graphic novel, take a look at a page in a slightly different way. After you've read it from panel to panel, have a look at the page as a whole. Plenty of comic pages are, admittedly, just one panel laid out after another. But sometimes you hit a page that does something magical, either subtly or forcefully. It takes control of your eye and guides it on a journey through the images in a manner no other medium possibly could. Maybe it's about how the panels are laid out in relation to one another or maybe the figures guide you with their placement and body language effortlessly through the narratie or possibly the elements of the page comment on the very form itself. A good place to start is with the work of Jack Kirby, who was considered the King for a number of reasons, but among them was his ability to plumb these possibilities and turn a single page into a work of art that deepens and magnifies the overall experience of reading the story.