function image_popup(url, xsize, ysize, scrollbar) {

var myWidth = 0, myHeight = 0;
myWidth = screen.Width;
myHeight = screen.Height;

day = new Date();
id = day.getTime();
xpos = (myWidth/2) - (xsize/2);
ypos = (myHeight/2) - (ysize/2);

eval("page" + id + " = window.open(url, '" + id + "', 'toolbar=0,scrollbars="+scrollbar+",location=0,statusbar=0,menubar=0,resizable=0,width="+xsize+",height="+ysize+",left="+xpos+",top="+ypos+"');");
}