Loading Graphics Before You Display Them
Many sites include rollover effects to make images change when the mouse moves over them. However, sometimes there's an unsightly delay while the second graphic is downloaded from the server. You can avoid this delay with some scripting code to make the client's browser to load the second graphic at the same time as the page.
In fact you can pre-load several graphics using the same technique. Here's a JavaScript function to include the header section of your page:

<SCRIPT LANGUAGE="JavaScript">
function loader()
{
preLoad = new Array();
for (i = 0; i < 5; i ++)
{
preLoad[i] = new Image();
}
preLoad[0].src = "first.gif";
preLoad[1].src = "second.gif";
preLoad[2].src = "third.gif";
preLoad[3].src = "fourth.gif";
preLoad[4].src = "fifth.gif";
}
</SCRIPT>

Call it by including ONLOAD="loader()" in the page's <BODY> tag and it will load five graphics into the array preLoad ready for displaying. The code can easily be extended to cope with pre-loading as many graphics as you need.