ultra-compact: A type of digital camera that's the size of a credit card, with a depth of less than 1 inch, that fits comfortably in a front jeans pocket.

underexposed: When too little light hits the camera’s film or image-sensor array, creating an image that’s too dark.

upsample: Add pixels to a digital image.

USB: Stands for Universal Serial Bus. A type of port now included on most computers. Most digital cameras come with a USB cable for connecting the camera to this port.