Here is a very impressive video on a new technique for resizing images called seam carving. The software can detect what are the least important areas in an image and use that model to let you fluidly resize a picture while minimizing the loss of information. You have to see it to believe it. The end result is that you can resize or manipulate part of the picture while making sure that it continue to looks good [note: The presentation is also a good example of the power of story telling].
For more information:
(Thank you Olivier)