13.3. Exporting and Converting Pictures

13.2. One-Click Desktop Backdrop

iPhoto's desktop-image feature is the best way to drive home the point that photos of your children (or dog, or mother, or self) are the most beautiful in the world. You pick one spectacular shot to replace the standard Mac OS X swirling blue desktop pattern. It's like refrigerator art on steroids.

Creating wallpaper in iPhoto is so easy that you could change the picture every day ”and you may well want to. In iPhoto, click a thumbnail and then click the Desktop button on the bottom panel (or choose Share Desktop). Even though the iPhoto window is probably filling your screen, the change happens instantly behind it. Your desktop is now filled with the picture you chose.

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Note: If you choose several thumbnails or even an album, iPhoto assumes that you intend to make Mac OS X rotate among your selected photos, displaying a new one every few minutes on your desktop throughout the day. To confirm its understanding, Mac OS X opens up the relevant panel of System Preferences, so that you can click the Desktop tab and specify how often you want the photos to change.

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Just three words of advice. First, choose a picture that's at least as big as your screen (1024 x 768 pixels, for example). Otherwise, Mac OS X will stretch it to fit, distorting the photo in the process. (If you're really fussy, you can even crop the photo first to the exact measurements of the screen; in fact, the first command in iPhoto's Constrain pop-up menu [page 150] lists the exact dimensions of your screen, so you can crop the designated photo [or a copy of it] to fit precisely.)

Second, horizontal shots work much better than vertical ones; iPhoto blows up vertical shots to fit the width of the screen, potentially chopping off the heads and feet of your loved ones.

Finally, if a photo doesn't precisely match the screen's proportions , note the pop-up menu shown at bottom in Figure 13-2. It lets you specify how you want the discrepancy handled. Your choices include:

• Fill screen. This option enlarges or reduces the image so that it fills every inch of the desktop. If the image is small, the low-resolution stretching can look awful . Conversely, if the image is large and its dimensions don't precisely match your screen's, parts get chopped off. At least this option never distorts the picture, as the "Stretch" option does (below).

• Stretch to fill screen. Use this option at your peril, since it makes your picture fit the screen exactly, come hell or high water. Unfortunately, larger pictures may be squished vertically or horizontally as necessary, and small pictures are drastically blown up and squished , usually with grisly-looking results.

• Center. This command centers the photo neatly on the screen. If the picture is larger than the screen, you see only the middle; the edges of the picture are chopped off as they extend beyond your screen.

  But if the picture is smaller than the screen, it won't fill the entire background; instead it just sits right smack in the center of the monitor at actual size . Of course, this leaves a swath of empty border all the way around your screen. As a remedy, Apple provides a color -swatch button next to the pop-up menu. When you click it, the Color Picker appears, so that you can specify the color in which to frame your little picture.

• Tile. This option makes your picture repeat over and over until the multiple images fill the entire monitor. (If your picture is larger than the screen, no such tiling takes place. You see only the top center chunk of the image.)

And one last thing: If public outcry demands that you return your desktop to one of the standard system backdrops, open System Preferences, click the Desktop & Screen Saver icon, click the Desktop button if necessary, choose Apple Backgrounds or Solid Colors in the list box at the left of the window, then take your pick.

Figure 13-2. If your photo doesn't fit the screen perfectly , choose a different option from the pop-up menu in the Desktop & Screen Saver preference panel.
While you're in the Desktop & Screen Saver or Screen Effects preferences pane, you might notice that all of your iPhoto albums are listed below the collection of images that came with your Mac. You can navigate through those albums to find a new desktop image. This approach isn't as fast (or fun) as picking pictures in iPhoto, but if for some reason iPhoto isn't open on your Mac (heaven forbid !), you can take care of business right there in System Preferences.