This video, from a presentation at SIGGRAPH, shows a demo of a technology that can dynamically edit the content of an image so that it can be resized and still look “correct,” regardless of dimensions. It seeks out and removes areas of an image that have the least amount of a given “energy” in them (say the gradient magnitude function). The process is known as “seam carving” and looks quite extraordinary. At the end of the demo, the authors show how these techniques could be applied in a photo editing program.
The SIGGRAPH paper explaining this image tech can be found here [PDF]