A friend of mine often asks me to shrink hi-res photos down for her. The original files are usually several MGs, print quality, and she usually wants to use them in an email newsletter, or on the web.
Tonight I found
http://www.shrinkpictures.com/
which did a great job of shrinking an image that was 2800kbs to 34kbs when I selected the default settings.
In case you ever need to shrink an image but aren't an image editor (PSD) user. If you want to learn more about hi res/low res, here's a tutorial.