var myPix = new Array("images/pathfinder.gif", "images/surveyor.gif", "images/surveyor98.gif");
var thisPic = 0;

function processPrevious() {
     if (document.images && thisPic > 0) {
          thisPic--;
          document.myPicture.src = myPix[thisPic];
     }
}

function processNext() {
     if (document.images && thisPic < 2) {
          thisPic++;
          document.myPicture.src = myPix[thisPic];
     }
}

</SCRIPT>

<IMG SRC="images/pathfinder.gif" NAME="myPicture">

<A HREF="javascript:processPrevious()">Previous</A>
<A HREF="javascript:processNext()">Next</A>