Preview is a catch-all file viewer, handling a variety of image formats as well as the ubiquitous portable document format, otherwise known as the PDF, which was introduced by Adobe in 1993, and was released as an open standard in 2008. One thing Preview has had trouble with, until now, has been adding extra pages to a PDF document.
Not anymore, as the Mountain Lion version of Preview will let you add pages to PDF documents on the fly. Here’s how.
This tip isn’t too tricky, though, as there’s a menu item to do it for you.
Launch Preview with a double click on the Applications folder, or just double click on a PDF file. Click on the View Menu button in the upper left of the opened window, and choose “Thumbnails” from the menu at the top of the popup. A column will open on the left hand side of your document that contains thumbnails of all the pages in your PDF document.
Using the thumbnail column, click on the page before the spot where you’d like to insert the new addition. Click on the Edit menu at the top of your Mac’s screen, and move your mouse down to Insert. Choose either Page from Scanner, Page from File, or Blank Page from the options in the Insert menu. The inserted page will go into your PDF document after the page you selected above.
Now you can add pretty much anything you can scan or download, or just a big white blank page, in any PDF that Preview can handle. Happy page adding!
Source: Mac Life