Apple Keynote 2 - Manual (Page 10)

10 Preface Welcome to Keynote 2
Easy-to-Use Media Tools
Preview items in your iPhoto or iTunes Library, or your Movies folder, and drag them
right to a slide.
Use the Mask feature to reveal only the part of an image you want to focus on,
without altering the original image file.
Use a mask to frame
part of a photo. Drag an image, movie, or
audio file from the iLife
Media Browser to a slide.