Hi @roseannehanalei, you should check out our featured questions on Using Houzz:

https://www.houzz.com/discussions/home-and-garden-discussions-dsbr0-bd~

Particularly:

https://www.houzz.com/discussions/how-do-i-create-a-new-ideabook-dsvw-vd~31916

And:

https://www.houzz.com/discussions/how-do-i-delete-a-photo-in-my-ideabook-dsvw-vd~31915

Basically what you will need to do is add all of the images in your massive ideabook that you want to be in an additional ideabook and then go back and delete them from the first ideabook. Good luck!