And larger number of pixels means larger file size to store! If you take pictures at 6MP resolution, the resulting JPEG file may be about 3 MB in size (it actually depends on the scene being photographed as well as compression setting of your camera). For a 4" x 6" printout, the 3MP resolution is sufficient as raru has noted (but it doesn't hurt to have a camera with 6MP or higher resolution, because you can adjust the actual resolution before taking a shot). If you view it online on your computer monitor and don't ever make a printout, then even a smaller resolution is sufficient (only 1MP is sufficient for a picture to be viewed full-screen on a XGA monitor).