The new smart image resizing, retargeting, and cropping technology for images and photos called seam carving is amazing and downright brilliant. This was an algorithm developed invented by Dr. Ariel Shamir and Dr. Shai Avidan. This is really cool and helpful to do instead of resizing an image with a focal area that gets distorted this method starts by letting you mark the important target to keep then in simple terms starts by removing parts of the photo or adding based on priority of the calculated horizontal and vertical seams.
Check out the Youtube video recording of a presentation at SIGGRAPH 2007 showing the pure magic and application of seam carving.
There is now a web 2.0 online free version. Check out a photo and resizing it and you can also carve someone out of a photo.
There was also a free plugin that added seam carving for Photoshop but it appears Adobe hired the person and then removed the free plugin download.
Cheers,
Shaan