Posting pages with large images? Use PNG!

I've been looking at web safe colour palettes for colours for the revamped homepages today. Since I can use the browser identity string to determine which platform is rendering the page, I am toying with the idea of slightly different palettes for different browsers, but using interlaced PNG files for the larger pictures on the site instead of JPEG files. I've found this page to be a useful guide to the format: nuwen.net - Introduction to PNG. There are tools for manipulating images referenced on the site too.