To insert one page after one specific page, there are two steps:

1. Add one new page to your book and this page will always be added to the end of your book as the last page of your photo book.

2. Open Rearrange Pages window from the Book menu. With the help of the thumbnails of all the pages, you should be able to move the added page after one specific page. Do not forget to hit Save Changes before leaving this screen.

When you insert one page into your book, this action also changes the way your pages are laid out. Just be sure to preview all the pages again to see if the pages still fall the way you prefer.