function switchIMG(type,img) {
	layer = 'main';
	if (document.layers) {
		document.layers[layer].document.images[img].src = type.src;
	} else {
		document.images[img].src = type.src;
	}
}


function image_init() {
	counter = 1;
	mainImg.src = imagesequence[counter];
	switchIMG(mainImg,'main_image');
}


function btnGoBack() {
	counter = counter - 1;
	if (counter <= 0) counter = maxImg;
	mainImg.src = imagesequence[counter];
	switchIMG(mainImg,'main_image');
}


function btnGoForward() {
	counter++;
	if (counter > maxImg) counter = 1;
	mainImg.src = imagesequence[counter];
	switchIMG(mainImg,'main_image');
}