@wion The difference between a comic and a graphic novel is the same as between short stories and novels, or a TV episode and a movie. The comic is plotted to be contained within that 20-30 page range. A graphic novel, if well done, has a longer fuse and a more involved story.
As for the last, if you don't actually NEED the pictures to fully tell the story, then you don't have a graphic novel, just a story that's illustrated.
As for the last, if you don't actually NEED the pictures to fully tell the story, then you don't have a graphic novel, just a story that's illustrated.