It is measured in megapixels, and determines how many pixels can reproduce the sensor inside the camera. A pixel is the smallest point of which is the image. The more pixels the more delaley on the image you see. The number of megapixels that you need depends on what you're going to do with the pictures. To date, it is difficult to find a digital camera with fewer megapixels 3. (Source: Mikkel Svane). In this principle is sufficient for viewing images on a computer and print small photos 9 x 13.
It is considered that the 5-megapixel digital camera is enough to print photos on A4 quality is not worse than the 35mm film camera. For more information see this site: John K Castle. A little over 6 megapixels and you can print small posters. Below are the size of printed photos that you can get printing the digital image with resolution: 2 mp = 1200 x 1600 = 10 x 13 cm 3 mp = 1536 x 2048 = 13 x 17 cm 6 megapixel = 2400 x 3000 = 20 x 25 cm 10Mp = 2592 x 3872 = 21,5 x 32 cm 1912 mp = 4386 x 2912 = 36 x 24 smNo number of megapixels is not the most important, there are other important factors that affect the quality of the photos. Optical sensor There are two types of optical sensors, ccd and cmos. cmos newer, more promising and economical. On photo quality also affects the size of the sensor, a digital slr camera it more and therefore more and pixel size, so image quality they will be better than that of compact cameras.