In Photoshop CS4, Adobe introduced an amazing featured called "Content-Aware Scaling," which intelligently changes an image's proportions without altering the important subject matter. (To see examples, read Review: Adobe Photoshop CS4.)

Now something that looks a lot like Photoshop's Content-Aware Scaling is available for the iPhone. Liquid Scale 1.0 sells for $1.99 on the App Store. Its creator, Savoy Software, says that Liquid Scale can "scale images in any way without distorting or reducing the motif. It is even possible to move two motifs closer together or remove individual persons out of the image."

You can let the software decide what stays and goes, or you can mark areas for subtraction. You can save the resulting images as low, medium, or high quality and store them on your phone or email them.