I just got a Canon S5 IS and LOVE IT! When I shoot in full size, the quality is outstanding, rich, and detailed. However, when I reduce photo size (either in Zoombrowser for emailing or in Roxio's Photosuite), the quality naturally drops. Since I shoot for a website, what I want is a higher quality photo but a smaller size. Based on that, is it better for me to reduce the actual size of the image shot but keep the resolution? Does that still give me the advantage of the 8 megapixels? Is there a downsize to doing this?

Most of my pics on the site are either 700X700, 400X400, or 175X175. I can take a beautiful full size shot but it gets pretty average when I size it down to 400X400, and worse when I get it to 175X175.

Also, I shot a ton of photos with a Nikon D80 in full size. What is the best way to keep the quality, but reduce the size of the actual image?