What is a megapixel and how many do I need?
Megapixel (MP) is a term describing digital camera resolution, referring to the total number of pixels in the square area of the CCD (charge-coupled device). One megapixel equals a million pixels. For posting pictures on a Web site, e-mailing them or making slide shows for your PC or TV screen, low- to mid-level resolution (under 1 megapixel) will suffice. If you intend to print your pictures out and need a high-quality, data-rich image, you want at least a 2-megapixel model. Remember that the capabilities of your printer and the paper you use will bear heavily on the quality of printed photos, regardless of the resolution of your camera.
