How to Edit Photos in iPhoto

By Mark L. Chambers from Mac OS X Snow Leopard All-in-One For Dummies

iPhoto includes several image editing tools that you can use to correct common problems in your pictures, such as red eye. You can use the editing tools to rotate images, retouch photos, or enhance the colors to bring out the best.

The first step in any editing job is to select the image you want to fix in the Viewer. Then click the Edit button on the iPhoto toolbar to switch to the Edit mode controls. Now you’re ready to fix problems using the editing tools. (If you’re editing a photo that’s part of an Event, album, Faces, or Places, note the spiffy scrolling photo strip at the top, which allows you to switch to another image to edit from the same grouping.)

When you’re done with Edit mode, click the Done button.

Rotate: Click the Rotate button to turn the image counterclockwise once. Hold down the Option key while you click the Rotate button to rotate clockwise.
Straighten: Click the Straighten button and then drag the slider to tilt the image in the desired direction. Click the Close button to return to Edit mode.
Enhance: If a photo looks washed out, click the Enhance button to increase (or decrease) the color saturation and improve the contrast. Enhance is automatic, so you don’t have to set anything.
Remove red-eye: Unfortunately, today’s digital cameras can still produce the same “zombies with red eyeballs” as traditional film cameras. Red-eye is caused by a camera’s flash reflecting off the retinas of a subject’s eyes, and it can occur with both humans and animals.

iPhoto can remove that red- and green-eye. Click the Red-Eye button and then select a demonized eyeball by clicking in the center of it. (If the new eyeball is too small or too large, drag the Size slider to adjust the dimensions.) To complete the process, click the X in the button that appears in the image.
Retouch: The iPhoto Retouch feature is perfect for removing minor flecks or lines in an image (especially those you’ve scanned from prints). Click Retouch and the mouse cursor turns into a crosshair; just drag the cursor across the imperfection.
Switch to black-and-white or sepia: Ever wonder whether a particular photo in your library would look better as a black-and-white (or grayscale) print? Just click the Effects button to display the Effects window, which offers eight different effects you can apply to the photo.
Adjust photo properties manually: Click Adjust to perform manual adjustments to brightness and contrast, as well as the sharpness, shadow, and highlight levels. To adjust a value, make sure that nothing’s selected in the image and then drag the corresponding slider until the image looks the way you want. Click the Close button to return to Edit mode.

While you’re editing, you can use the Next and Previous buttons at the lower-right corner of the iPhoto window to move to the next image in the current group (or back to the previous image).