1. A method of improving the functioning of a cell phone, the cell phone including a battery, a camera, and a processing system, the cell phone further being equipped to perform plural different types of image recognition operations including at least barcode recognition and digital watermark decoding on frames of imagery captured by the camera, the method comprising the acts: performing a plurality of preliminary image processing operations on each of 15 or more frames of imagery captured per second, said performing requiring application of less than 10% of computational capabilities of the cell phone processing system, said preliminary image processing operations including analyzing each of said frames of imagery to determine at least one of: a colorfulness metric, a color saturation metric, or a contrast metric, said preliminary image processing operations yielding intermediate data, including said determined metric, for each of said frames; (a) based at least in part on said determined metric, performing a barcode recognition operation and not a digital watermark decoding operation on a first of said frames of imagery captured by the camera; (b) based at least in part on said determined metric, performing a digital watermark decoding operation and not a barcode recognition operation on a second of said frames of imagery captured by the camera; wherein said barcode recognition and watermark decoding operations are performed using said cell phone processing system, without off-loading to a processor remote from the cell phone; and wherein a type of image recognition process performed on a frame of captured imagery, as well as a type of image recognition process not-performed, are based on said determined metric; wherein the cell phone does not perform all of said plural types of image recognition operations on said first or second frames of captured imagery, but rather selects among said plural types of image recognition operations based on imagery characteristics, thereby conserving battery power and processing resources, despite performing said barcode recognition and watermark decoding operations using said cell phone processing system without reliance on a processor remote from the cell phone.