Pictures are rated in dots per inch (dpi). Digital cameras are rated by the number of megapixels (1 megapixel = 1,000,000 pixels). Each pixel represents a dot on a picture. To get a good quality print, images need to be a minimum of 300 dpi. The table below shows the maximum size of an image at 300 dpi for a given megapixel camera.
Resolution in Megapixels	1	2	3	4	5
Typical Highest Resolution	960 x 1280 1200 x 1600 1536 x 2048 1704 x 2272 1920 x 2560 3 x 4 4 x 5 5 x 6 5 x 7 6 x 8
Largest image size at 300 dpi