function show_image(url, width, height)
{
var window_offsetX = 0, window_offsetY = 0, tmp;
if (window.screen.availWidth > width)
{
tmp = (window.screen.availWidth - width)/2;
if (tmp >= 0) window_offsetX = tmp;
}
if (window.screen.availHeight > height)
{
tmp = (window.screen.availHeight - height)/2;
if (tmp >= 0) window_offsetY = tmp;
}
var picwindow = window.open("", "", "width="+width+",height="+height+",left="+window_offsetX+",top="+window_offsetY+",scrollbars=yes,resizable=no,dependent=no");
picwindow.document.write(""+url+"");
picwindow.document.write("![](\""+url+"\")
");
picwindow.document.close();
}