Unless your digital camera has a built-in orientation sensor, iPhoto imports all photos in landscape orientation (wider than they are tall). The program has no way of knowing if you turned the camera 90 degrees when you took your pictures. Once you’ve imported the photos, just select the sideways ones and rotate them into position (if indeed you didn’t do so during your first slideshow, as described on page 95).
You don’t have to be in Edit mode to rotate photos. Remember, you can select thumbnail images when you’re in Organize mode and then use one of the following methods to turn them right-side up:
Choose Edit → Rotate → Counter Clockwise (or Clockwise).
Click the Rotate button in the main iPhoto window, just under the Info pane (it’s the rightmost of the four buttons on the pane). (Option-click this button to reverse the direction of the rotation.)
-R to rotate selected photos counter-clockwise, or Shift-
-R to rotate them clockwise.
Control-click a photo and choose Rotate → Clockwise (or Counter Clockwise) from the shortcut menu.
After importing a batch of photos, you can save a lot of time and mousing if you select all the thumbnails that need rotating first (by