Find advice on any digital camera in our resource center. The sensor is the heart of all digital cameras. It's the electronic chip that takes incoming light and converts it to a digital file. The density of the sensor determines a camera's overall picture quality. The photosites take the incoming light from the camera's lens and convert it to a digital file.
Resolution refers to the number of pixels in a picture.
To better visualize what a pixel is, look at a color newspaper photograph under a magnifying glass. The small sensor in a VGA camera captures just 300,000 pixels. These pixels are arranged in rows and columns. A VGA image has 640 rows and 480 columns of pixels, hence a resolution of 640x480. If you try to enlarge the print any further, you're going to see some image degradation, because there just isn't enough information in a 300,000 pixel image to enlarge a photo beyond 4 x 6.