If you've uploaded photos to your Paper Culture account you may notice they don't appear in the photo book editor. At this time, uploading photos for photo books is separate from the folders your photos for cards are in. The photos you see in your account's profile would only be accessible from card personalization. You will need to upload your photos in the photo book editor so that they can be applied to your photo book project.
For help with creating your book visit this article that visually walks through how to do the process: How do I personalize my photo book?