by , 7:30 AM EDT, April 4th, 2008

Preview is a powerful application that can do many things. One of the new features introduced in Leopard is the ability of Preview to merge several files of different types into one, say, PDF document.

This can be particularly handy when you want to add a graphic or an additional page or two to an existing PDF file. That has been hard to do before Leopard.

Let's say we have an existing PDF file like the one shown below. Open it in Preview. Under the View menu, select Sidebar (shown in the red circle) if it isn't already visible.

Now open the file you want to add in Preview, too. It could be another PDF, but I used a JPG in this example. Open its Sidebar as well. You should see something like the screen shot below.

Here's the cool new feature in Leopard. Drag the new graphic's thumbnail image from one Sidebar to the other, as I've shown with the red line. Just drop it underneath the first image because you can reorder later. If desired you can drag more files into the first document's Sidebar in the same fashion. When you have them all, just drag a thumbnail up or down within the Sidebar to reorder. In this example, I dragged the thumbnail image of Moscone West, a third file I added, to the top.

Finally, go to Preview's File menu and save the document in the format you desire. In this example I saved it as a PDF. Once you have the file saved, you can have fun verifying the multi-page PDF file with Quick Look by selecting it and then hit the spacebar. A final tip: multi-page docs in Quick Look will have scroll bars when you view them.