When you create a book, iPhoto automatically assigns a layout to each page and places photos on the pages. You can change the layout of a book page at any time.
The book theme you use determines the available page layouts. Page layouts can include up to 16 photos, a single photo displayed across a page spread, maps, text, and more.
To change a book page layout:
The book pages appear in All Pages view.
Double-click the page on which you want to change the layout.
iPhoto updates to show the page spread, with the page that you double-clicked selected.
Click the Layout button in the toolbar.
The page layout tools appear in the Layout pane.
In the Layout pop-up menu, choose a type of page layout (a number of photos per page, a map, a blank page, and more), and then select one of the page layouts that appear.
You can also change a book page layout by clicking the page number below the page and using the formatting tools that appear above the selected page.
To turn “Auto-Layout pages” on or off:
When you change a page layout, iPhoto automatically places photos on pages based on the photo’s size and orientation (horizontal or vertical). You can easily turn the auto-layout feature on or off.
Click the Options button in the toolbar.
Click the Book Settings button in the Options pane.
Select or deselect the “Auto-Layout pages” checkbox.