So what about megapixels? Despite marketing hype, they are a measure of quantity not quality. Pixels are a measure of the number of photoreceptor sites on your camera's image sensor, which determines the amount of data that can be captured. That, in turn, defines how large a photo can be printed and how much you'll be able to see when you zoom in on details before the picture begins to blur or pixelate (break up into its component dots).

Choose the megapixel rating of your digital camera based on what you plan to do with your pictures. For the Web or e-mail, too much data is actually counterproductive, slowing down transmission without increasing image quality. If all you plan to do with your pictures is e-mail them or display them on the Web, anything more than 3MP is overkill. VGA or XVGA resolution can be adequate. A 2MP camera will probably capture more than enough data for the Web or e-mail, but such cameras have fewer features. You can, however, set any camera to take pictures at appropriate resolutions, for example for e-mailing.

While megapixels are not a measure of quality, it's generally true that the more pixels a camera can capture, the more expensive a camera is to build. Therefore, other higher-quality components may be included, which can result in a better image.

To see how megapixels correspond to image quality, see "Choose Your Camera".

If you print your photos, this table is a general guideline for how large your output can be for each resolution (dimensions in inches):

1.3MP 3.5 x 5 to 4 x 6

2MP 4 x 6 to 5 x 7

3MP 5 x 7 to 8 x 10

4MP 8 x 10 to 8.5 x 11

5MP 8.5 x 11 to 9 x 12

6MP 9 x 12 to 11 x 14

8MP 14 x 17 to 16 x 20