Size matters -- not megapixels
In my film camera days, a roll of 35mm film gave you a negative of 36 x 24mm. That area was the "recording surface" for the images I shot. Digital cameras today are promoted for having 8, 10, or 12 megapixels. That's not the size of the recording surface; it's geek-speak for the number of tiny recording cells on the sensor. You can squeeze millions of these cells on a sensor. But if the sensor itself is only 7.2 x 5.3 mm -- typically the size found in a pocket digital camera -- you have less overall area in which to capture an image. Add megapixels, and you're just squeezing more tiny cells on a small sensor, which leads to image degradation in the form of "noise." So, when you're looking at different cameras, megapixels are irrelevant. It's the size of the sensor that really determines image quality. There's a semi-technical explanation of this at this web site, and a simpler (and somewhat exuberant) discussion on Ken Rockwell's webs...