Photo retouching — with programs such as Photoshop, or the open source clone Gimpshop version of the GNU Image Manipulation Program — can be used to doctor images (sometimes obviously, and sometimes inobviously). I’m more of a programmer than a graphics artists, so I usually just do a quick cropping, resizing and sharpening of my JPEG photographs using Irfanview. This means that the proportions within the image remain the same.
Download Squad pointed out a “next gen image resizing method”, linking to a prior news item about a 4-1/2 minute Youtube video where Shai Avidan demonstrates “Seam Carving for Content-Aware Image Resizing”, for a recent SIGGRAPH conference. It’s fun to watch the video, because it alters images in a way similar to the way human beings do: it keeps the key content (e.g. people) in natural proportion, while removing out some of the uninteresting (or “dead space”) content (e.g. sky).
There’s a feature to mark faces or people specifically to not be resized — or specifically to be removed. Near the end of the demo, a photograph of a couple in a street scene is shown with the man removed, and then the woman removed.
This reminds me of movies about bad breakups — ex-spouse, ex-boyfriend/ex-girlfriend, ex-buddy — where a person loves a photograph, but wants to clip the other person out of it. It looks like this feature could be automated in a photo retouching program soon.