From Photojojo blog, a method of resizing a photo in which the computer analyzes the photo to determine what's important in the image, then eliminates first the areas that are not important as the image is sized down. "That means you can resize a photo to be half as wide without shrinking everyone in it, or even make a photo wider without making it look stretched. You can even pick areas you definitely want to leave alone, or areas you definitely want to lose, making it a super easy way to remove an ex or a stranger from a otherwise lovely photo." Works more or less as proportional spacing does with fonts, I believe. Also called content-aware image resizing.