Instead of film, a digital camera has an imaging sensor consisting of millions of pixels. To record an image, each pixel builds up a tiny charge of electricity in response to the light it "sees." A megapixel is the term used for a million pixels — and the more megapixels an imaging sensor has, the higher the camera's potential resolution.
Now, once upon a time, megapixels were the big differentiator in cameras — because if you didn't have enough megapixels, you couldn't get a high enough resolution for good photo prints. Fortunately, most new cameras today offer 6 megapixels or more — ample resolution for small and larger print sizes, including 8" x 10" photos.
Type of image Minimum resolution needed Number of megapixels needed
Web image 640 x 480 1-megapixel cameras* & up
4" x 6" print 2048 x 1536 3-megapixel cameras* & up
8" x 10" 3072 x 2048 6-megapixel cameras & up
16" x 20" 3264 x 2448 8-megapixel cameras & up
* Top counts of 1, 2 or 3 megapixels are mainly seen only in today's cell phones and camcorders.
So if most cameras can deliver the print sizes you need, how do you decide between, say, a camera with 8 megapixels and a camera with 10 megapixels? You may not need to. The difference in resolution between their photos can be difficult to detect, unless you're a pro who looks for the tiniest details, or you plan to make really enormous prints.
With that in mind, you may want to instead consider your photography habits and decide what other camera features are particularly important to you. Do you want extra zoom capability to capture close-ups of your child across the baseball field or wildlife in a distant tree? Are you mainly interested in automatic functions, or do you want to experiment with camera settings on your own? Are you looking for an ultra-slim model that you can easily carry everywhere?