[Gorwingel]

I have been able, even though I did see FOTR first, to create images of my own while reading the books. I think it is because when I read the book I found that many of the characterizations of the characters in the movie really didn't fit with the book (in the film the characters are much simplified, in the book they are much more complicated with more depth). When I read the book my Frodo is a much wiser, intelligent and less naïve character, much different than the annoying (at times), less intelligent (it seems), younger film Frodo.
And I have also been able to conjure up my own images of locations (like Rivendell), in which the film really didn’t match my personal image of what it should look like. And additionally I also agree with zb. Some of the things that Tolkien describes in the books are very hard to actually come up with an image of (my example being the lights on the Dead Marshes, or the Balrogs). I think that now I have actually been more affected with images of the villains than the good guys. I will always think of the film Balrog instead of an image that I could have come up with on my own if I would have read the books before the films.