I've noticed that whenever I produce smaller images (e.g. 640 x 480 pixels for an eBay listing) from my G2 shots, the sharpness is degraded. I would like to understand why this is. For example if I take a large resolution shot (4 MPixels) and then resize it to 640 x 480 using Paint Shop, it doesn't look as sharp as the original. With both the original and the shrunk image, I'm viewing the image in a 640 x 480 pixel area of the screen.
I've tried shooting at 640 x 480 (small resolution) so that no resizing is necessary and still the shots don't look sharp.
The thing that confuses me is that when I view an image in a 640 x 480 area of my monitor, it doesn't seem like a higher resolution image (e.g. 1280 x 960) can provide any more information to the 640 x 480 pixels that are actually displayed than a low resolution image that is 640 x 480 to begin with. Why does the image captured at higher resolution it look sharper in this situation?