Use the highest resolution and the lowest compression settings on your camera. Many digital cameras provide adjustable resolution and file compression settings. In general, reducing file size allows you to store more pictures on a memory card. The tradeoff is lost picture detail. Less detail is typically not a problem when displaying pictures on a computer monitor but, depending on the size, can reduce the quality of a print.
Digital cameras use light-sensitive electronic sensors in place of film.
Megapixel cameras use sensors containing one million or more pixels . You can easily estimate your camera's maximum resolution by multiplying the number of horizontal by the number of vertical pixels. These specifications are typically printed in the user manual or on the outside of the original camera box. You can use this simple multiplication process to approximate the maximum resolution of any digital camera. Ultimately, the decision comes down to your personal quality expectations and needs.