Why do I have to use iPhoto to add photos to iBook Author?

As a photographer my photos are all in Lightroom and I use Photoshop. I don't own and don't intend to own Aperture and have long since stopped using iPhoto. While I love Apple products and own lots of them, I don't want to have to maintain a separate system just to use iBook Author. I've been wanting some time to play with this for ages and have some ideas for books that I really want to play with but .... photos and video are an issue for me. I don't use iMovie either, I use either Final Cut Pro or Premiere. Please, please tell me there is another way to use media with iBook Author???

Frustrated ....