This tip is originally from Google.
To make the pages load a lot faster all repeating images should be replaced by just 1 image + CSS code.
All smilies, all icons etc. should be on just one big image and the images should be placed with <div class="image_name"></div> code that will display the image as normally.
It will bring down the requests per page to the server from 50-100 to just 1-2. It will have a big impact on loading time at the user side and lessens the load on the server.