First, you need to understand what a pixel is. In terms of digital prints, a pixel simply means a dot of color that makes up the image. A mega-pixel is equal to one million pixels. The more mega-pixels a camera has, the greater the amount of information it records.
The easiest way to decide what to look for is to know what size prints you are likely to print from your camera. A one mega-pixel camera is fine for those who don’t plan on printing photos but rather just post them on the internet. A small print, say 4 x 6, will print acceptably from this camera.
A 2 mega-pixel camera will enable you to produce good quality 5 x 7 prints and fair quality 8 x 10 prints. When you reach 4 mega-pixels you can print out excellent quality 8 x 10 prints and acceptable 11 x 17 prints and a 5 mega pixel camera will allow you to print out high quality 11 x 17 prints.
Most families find a camera in the 3.2 Mega-pixel range to be the best choice. The quality of both 5 x & and 8 X 10 prints is very good yet the files on your computer are not so large you need worry about not having enough space.
Any camera over 5 mega-pixels is unnecessary for all but professionals in photography; even then, only those who have need for poster-size prints find that many mega-pixels worth the money. Most freelance photographers find 4 or 5 mega-pixels to be sufficient for excellent-quality prints.
The choice is yours. Look to what you plan on doing with your photos and then decide. In most cases spending the money for increased optical zoom and lower mega-pixels is the best choice.