I have some photos from about 5 years ago taken with a 1 megapixel camera. Although I was thrilled with them at the time they now look a little blurry and “soft”. There’s no real detail. So how is is that the Mars Spirit Rover can take fantastic, detailed pictures with a 1 megapixel camera? This article explains: Digital Secrets: How Spirit Makes Great Photos
A Sony DSC-F717, with a street price of around $600, has 5.2 million sensors (or 5 megapixels) on a chip that is 8.8 by 6.6 millimeters (or .35 by .26 inches). The Pancam has just a million sensors spread across a chip that’s 12 by 12 millimeters — nearly a half-inch square. Each tiny Pancam sensor, measured in microns, is nearly four times as big as those on the Sony.