Flip between states of an image and compare it with others using gestures.
Image editing is a highly visual-orientated process. Colors are tweaked, unwanted elements removed, filters are added and so on. As a result it’s incredibly important to compare the altered image with the original; or sometimes with similar images in a collection.
It’s easy to compare an edited image with its original state in iPhoto, with just one tap of your finger. It’s also possible to compare multiple images in a grid, and even ask iPhoto to automatically display images similar to the one you’ve selected. In this tutorial you’ll learn how to do all of this in just a few simple steps.
1. Compare edits
When editing a photo, tap and hold the Compare button in the top corner of the screen to see the original version of the image. This is a great way to see if you’ve lost any important elements of the photo, or to see what great progress you’ve made.

2. Compare on a grid
To compare multiple photos on one screen, begin by tapping the thumbnails button. You’ll see all of your photos in the thumbnail grid down the side of the screen. Tap on one, then touch and hold your finger on a second image. You’ll see both appear in a separate window.

3. Get dragging
You can also drag photos from the thumbnail grid to the main window to add additional images.

4. Select more than two
Two compare a large number of images, simultaneously tap and hold on the first and last images from the range you wish to compare.

5. View similar photos
Double-tap on a photo to see similar images in a collection. If iPhoto hasn’t found any similar images then it will emit an alert sound.
