if( document.images )
{
<!--Small button-->
  but1 = new Image(177,22)  ;
  but1.src = "images/twt_button1_off.gif";
  but2 = new Image(177,22)  ;
  but2.src = "images/twt_button1_on.gif";

  but3 = new Image(177,22)  ;
  but3.src = "images/twt_button2_off.gif";
  but4 = new Image(177,22)  ;
  but4.src = "images/twt_button2_on.gif";

  but5 = new Image(177,22)  ;
  but5.src = "images/twt_button3_off.gif";
  but6 = new Image(177,22)  ;
  but6.src = "images/twt_button3_on.gif";

  but7 = new Image(177,22)  ;
  but7.src = "images/twt_button4_off.gif";
  but8 = new Image(177,22)  ;
  but8.src = "images/twt_button4_on.gif";

  but9 = new Image(177,22)  ;
  but9.src = "images/twt_button5_off.gif";
  but10 = new Image(177,22)  ;
  but10.src = "images/twt_button5_on.gif";

  but11 = new Image(177,22)  ;
  but11.src = "images/twt_button6_off.gif";
  but12 = new Image(177,22)  ;
  but12.src = "images/twt_button6_on.gif";

  but13 = new Image(177,22)  ;
  but13.src = "images/twt_button7_off.gif";
  but14 = new Image(177,22)  ;
  but14.src = "images/twt_button7_on.gif";
  }

<!--
function chkVer(imagename,objectsrc)
{
var n=navigator.appName
var v=parseInt(navigator.appVersion)
var browsok=((n=="Netscape")&&(v>=3))
var browsok2=((n=="Microsoft Internet Explorer")&&(v>=4))
if ((browsok)||(browsok2))
document.images[imagename].src=eval(objectsrc+".src")
}
//-->