function simg_prev() {
	if (t_img) {
		if (c_img>0) {
			c_img--;
			var img = image_url[c_img];
			if (img) { document.getElementById("itemimg").src=img; }
			else { c_img=0; }
		} 
	}
}

function simg_next() {
	if (t_img) {
		if (c_img<t_img) {
			c_img++;
			var img = image_url[c_img];
			if (img) { document.getElementById("itemimg").src=img; }
			else { c_img=0; }
		} 
	}
}