function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	var obj;
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			obj=document.getElementById(changeImages.arguments[i]);
			obj.src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		i_o_nas_over = newImage("images/o_nas-over.jpg");
		i_audio_over = newImage("images/audio-over.jpg");
		i_video_over = newImage("images/video-over.jpg");				
		i_studio_over = newImage("images/studio-over.jpg");
		
		preloadFlag = true;
	}
}