1. A method of handling images in a wireless device having an image processor coupled to an image sensor, the method comprising: transmitting windowing instructions to the image sensor, the windowing instructions specifying at least one of: (a) a size for a window on the image sensor, inside which window images are to be captured, and (b) a placement of a window on the image sensor, inside which window images are to be captured; receiving, from the image sensor, a digital image of a finger captured at the image sensor inside the window defined by the windowing instructions; and processing the digital image in a context of a plurality of previously received digital images to determine a finger motion indication.