function ShowImg(dir,name,width,height) {
 var w2 = width/2;
 var h2 = height/2;
 var x=(self.screen.width/2)-w2;
 var y=(self.screen.height/2)-h2;
 var s='left='+x+','+'top='+y+',';
 var s1='width='+width+','+'height='+height+',';
 var name = '/'+dir+'/'+name; 
 var fname='/cgi-bin/big.cgi?name='+name+'&w='+width+'&h='+height; 
 window.open(fname,'img',s+s1+'status=no,toolbar=no,menubar=no,scrollbars=no,resizable=no');
}