in camera , mega pixels worth nothing
its just a size of picture
quality matter
for snap shot mode , check for quality , shutter speed and aperature
for video ,
high resolution , clear quality
above 320 x 240 ,
but not 640 x 480 , or 720 x 360 is very good
term as 720p and 720p HD
others 1080p and 1080i
having minimum 30fps
