function popup_image(url) {
    imgwindow=window.open(url, "", "width=" + screen.availWidth + ", height=" + screen.availHeight + ",top=1,left=1,location=no,resizable=yes,toolbar=no,menubar=no,personalbar=no,scrollbars=no,status=no");
    imgwindow.focus();
}
function popup_image_sized(url, p_width, p_height, p_top, p_left) {
    if (p_width == 0 || p_width > screen.availWidth) p_width = screen.availWidth;
	else p_width = p_width + 20;
    if (p_height == 0 || p_height > screen.availHeight) p_height = screen.availHeight;
	else p_height = p_height + 20;
    if (p_top == 0) {
		if (p_height < screen.availHeight) p_top = (screen.availHeight- p_height) / 2;
		else p_top = 1;
    }
    if (p_left == 0) {
		if (p_width < screen.availWidth) p_left = (screen.availWidth - p_width) / 2;
		else p_left = 1;
    }

    urlwindow=window.open(url, "", "width=" + p_width + ",height=" + p_height +",top=" + p_top + ",left=" + p_left + ",location=no,resizable=yes,toolbar=no,menubar=no,personalbar=no,scrollbars=yes,status=no");
    urlwindow.focus();
}