In the digital camera domain, if there is one key number that marketers want to hype on, it is the megapixel number. When I get together with friends and relatives and we all whip out our digicams, the first question that everyone asks is “how many megapixels?” The megapixel topic almost always crops up when people ask for advise in what model to purchase.
The fact is “more megapixels” do not necessarily translate to “better pictures.” There are dozens of websites that present an entire technical discussion on pixels but lets just say that the megapixel value simply measures the amount of data of an image. It has nothing to do with clarity or picture quality. If you have a 12 megapixel camera with poor quality lens, you will basically end up with a 12 megapixel image of poor quality.
Then you have the file size factor. The translation from pixels to bytes is roughly triple. So the uncompressed file size of an image taken with, say, a 6 megapixel camera is approximately 18 megabytes. Not exactly something you would want to send to your relatives via email. Most digital cameras allow you to scale back the pixels or tweak the JPEG compression, all of which has the end result of a smaller file size but also a degradation of picture quality. Which is ironic because you bought a 6 megapixel camera to have the highest quality, right?