Welcome to the forums and congratulations on yoyr wedding. I hope you and your fiance have a wonderful day!
I'm guessing you must own a copy of Carcassonne already, otherwise it seems strange that you'd make a guestbook landscape from a game you've never played! So since there are no hi-res downloads here I'd also suggest scanning your tiles and using these images.
Good luck and please post updates as your project progresses! Would be to great to see how it develops.