I have a Canon PowerShot S30 3.2MP camera, it does a terrific job. I know about resolution. What about compression? I can set the images to L, M, or S compression. With L I get 77 images, with S I get 275 images on the card. I can't tell the difference in image quality, they're identical as far as I can tell. And the file sizes are the same. So what's the advantage of using the L or S compression settings?