Thanks to a forum member 'teabore' for spotting this pretty amazing new resizing technique from Dr Ariel Shamir and Shai Avidan of the Efi Arazi School of Computer Science. Revealed at SIGGRAPH this new method of image resizing looks for seams (not simple columns or rows) of pixels with the 'least energy' (least contrast / change in detail) both vertically and horizontally in the image and then uses this to enable resizing without losing important image content such as human subjects or other detail. This technique can be used for reducing and enlarging images as well as removing items from the image which are not wanted (by manually painting 'negative weight' over an area of the image). But less of my waffle just jump in and watch this video of the algorithm in use, I assure you it will make considerably more sense. (Purist photographers look away now).
Seam Carving for Content-Aware Image Resizing
Click here for more information on this technique
(20 MB PDF - slow downloading)