I'm one of the guilty ones who posted a photo that was 27 screens wide (sorry!) But just a question - the photos currently have a 300k limit, so a 250k file will still take X seconds to download on dialup, regardless of if it is a 480x360 or 1600X1200, it'll just have more or less resolution, correct?
480x360 looks like a convenient size for the reasons stated by Jim, but this should be independent of file size to some extent, isn't it? Are we confusing file size with image size?
(as a footnote, I've just completed reformatting my hard drive and am reloading all my software from scratch. When I have some photo editing software installed I'll see about reducing the image size a little and will re-load)