Often we find excellent wallpapers or photos which either do not fit in our monitor screen (w/o losing or distorting data while we try to resize them in photoshop or other image editors) OR often we want a custom size of images OR we get our hands on excellent images with weird unacceptable resolutiion, Siggraph 2007 presentation of an all new way to automatically resize images tracing 'seams' with the least amount of energy. The eraser thing at the end is totally worth it.

Checkout the video..