if (document.images)
{ // preload our rollover images
	imgWhatIsPROver = new Image();
	imgWhatIsPROver.src = "/images/sub_what_is_pr_over.gif";
	imgWhatCanPRDoOver = new Image();
	imgWhatCanPRDoOver.src = "/images/sub_what_can_pr_do_over.gif";

  // preload our normal images
	imgWhatIsPROff = new Image();
	imgWhatIsPROff.src = "/images/sub_what_is_pr_off.gif";
	imgWhatCanPRDoOff = new Image();
	imgWhatCanPRDoOff.src = "/images/sub_what_can_pr_do_off.gif";
}