function bild(xsize,ysize,picture)
{
    xp = (screen.width-xsize) / 2;
    yp = (screen.availHeight-ysize) / 2 - 30;
    
    site = "bild.htm?bild="+picture;
    winstr = "directories=0,location=0,menubar=0,resizable=0,scrollbars=0,status=0,toolbar=0,width="+xsize+",height="+ysize+",left="+xp+",top="+yp;
    WinBild = window.open(site, "", winstr);    
}