I am not sure if those rectangles are just solid colors or not. If they are you can alter your button styles to get the effect you are after. for example a 100 x 100 green box button:

<form action="http://yumazone.com" method="post" name="linker" target="_blank">
  <input name="link button" type="submit" style="background-color:#00FF00; border:0px; color:#6600FF; height:100px; width:100px;}
 " value="" />
</form>

This trick may not work in some browsers.