If you use a Multi-Touch trackpad or Magic Mouse, you can use gestures to perform certain frequent actions in iPhoto.
You can use trackpad gestures to navigate between photos while in single-photo view, and with Smart Zoom in grid, single-photo, and edit views.
In grid view, Smart Zoom remembers your zoom setting so that you can switch between it and the maximum zoom setting. In single-photo and edit views, Smart Zoom switches between minimum and maximum zoom.
To browse through photos, swipe two fingers across the trackpad.
If natural scrolling is turned on: Swipe left to go to the next photo, and swipe right to go to the previous photo.
If natural scrolling is turned off: Swipe right to go to the next photo, and swipe left to go to the previous photo.
You can turn natural scrolling on or off in the Trackpad pane in System Preferences.
To use Smart Zoom:
In grid view: Drag the zoom slider to the magnification you want, and then double-tap the trackpad with two fingers to switch between your selected setting and full magnification.
In single-photo and edit views: Double-tap the trackpad with two fingers to switch between minimum and maximum zoom.
You can use Magic Mouse gestures to navigate between photos while in single-photo view, and with Smart Zoom in single-photo and grid views.
In grid view, Smart Zoom remembers your zoom setting so that you can switch between it and the maximum zoom setting. In single-photo and edit views, Smart Zoom switches between minimum and maximum zoom.
To browse through photos, swipe one finger across Magic Mouse.
If natural scrolling is turned on: Swipe left to go to the next photo, and swipe right to go to the previous photo.
If natural scrolling is turned off: Swipe right to go to the next photo, and swipe left to go to the previous photo.
You can turn natural scrolling on or off in the Mouse pane in System Preferences.
To use Smart Zoom:
In grid view: Drag the zoom slider to the magnification you want, and then double-tap the top of Magic Mouse with one finger to switch between your selected setting and full magnification.
In single-photo and edit views: Double-tap the top of Magic Mouse with one finger to switch between minimum and maximum zoom.