Many people use Preview for viewing PDF files but it is also a good program for viewing slideshows of images. It even lets you add images to your iPhoto library with just one click of your mouse. In this tutorial, I'll describe Preview's slideshow options.

First, launch Preview (it's located in the Applications folder).

Set Preferences

1.  Open Preview's Preferences Pane and select the Images tab. Click in the circle in front of "Open all images in one window."

Add Images

2.  Add several images to Preview by dragging the images to the Preview icon in the Dock or by using Preview's Open... command on the File menu.

View Slideshow

3.  Select Slideshow from the View menu. The slideshow will open in full screen, with a control panel at the bottom of the screen.

Slideshow in Preview

Move Through Slideshow

4.  Use the arrow buttons on the control panel to move back and forth through the slideshow, one image at a time.

5.  You can pause the slideshow at any time by clicking the pause button (||). The button will change to a play button which you can click to resume viewing the slideshow.

Preview's slideshow pause and play buttons

View All Images at Once

6.  You can view smaller versions of all the images on one screen by clicking the Index Sheet button. Click one of the small images and it will become the only image on the screen. Note that you must select one of the images to return to the slideshow.

Preview's slideshow index sheet button

Fit Image to Screen

7.  Click the Fit to Screen button and the image will fill the screen. Note that the image might appear distorted or unclear when it fills the screen. Click the button again to view the actual size of the image.

Preview's slideshow fit to screen button

Add to iPhoto

8.  When you click the Add to iPhoto button, the image will be sent to iPhoto, and, after you click the Close button for the slideshow, iPhoto will open and the image you sent to it will be automatically imported into the program.

Preview's slideshow add to iPhoto button

Close Slideshow

9.  Click the Close button to leave the slideshow and return to the main Preview window.

Preview's slideshow close button

As you can see, Preview is a useful application for viewing groups of images, with the added benefit of being able to automatically add images to iPhoto.