Most digital cameras sold today support a resolution of 5 megapixels (million pixels) or higher. A 5 megapixel camera will allow you to print a 5 X 7 or 8 X 10 image of good quality. If you want to print larger photos, you will need a camera with 6 megapixels or higher. However, if you only plan to take images for the web or to email to friends and relatives, a 2 megapixel model should be good enough and cost less.
Do note that image quality is determined by the quality of the lens and other optics on your camera as much as by the megapixel value.