How many megapixels do I need?
As much as we'd like to give a one-word answer, this is one of the trickiest questions in digital photography, so we'll provide a short answer and a long answer.
Response: The short answer | The long answer
The short answer
For any images you plan to print or retouch, we recommend you stick to 3-megapixel resolution and higher; Web- and e-mail-only photos should be fine at resolutions below that. For prints 8x10 or larger, look for digicams with 4-megapixel resolution or higher.
The long answer
It depends upon what you're doing with the picture and how you're doing it.
Hint: If you're going to display or print pictures at smaller-than-actual-pixel size, resolution doesn't matter much--opt for the camera with the best color.
The images below were shot with a 2-megapixel and a 4-megapixel camera, respectively, and scaled down to smaller-than-actual size. Aside from slight color differences, they should look pretty similar.
Source:
www.Nytimes.com