$('sg2').observe('mouseover',   function() { $('sg2').setAttribute('src', 'images/sg/sg_ac_02.gif'); } );
$('sg2').observe('mouseout',   function() { $('sg2').setAttribute('src', 'images/sg/sg_02.gif'); } );

$('sg3').observe('mouseover',   function() { $('sg3').setAttribute('src', 'images/sg/sg_ac_03.gif'); } );
$('sg3').observe('mouseout',   function() { $('sg3').setAttribute('src', 'images/sg/sg_03.gif'); } );

$('sg4').observe('mouseover',   function() { $('sg4').setAttribute('src', 'images/sg/sg_ac_04.gif'); } );
$('sg4').observe('mouseout',   function() { $('sg4').setAttribute('src', 'images/sg/sg_04.gif'); } );

$('sg5').observe('mouseover',   function() { $('sg5').setAttribute('src', 'images/sg/sg_ac_05.gif'); } );
$('sg5').observe('mouseout',   function() { $('sg5').setAttribute('src', 'images/sg/sg_05.gif'); } );

$('sg6').observe('mouseover',   function() { $('sg6').setAttribute('src', 'images/sg/sg_ac_06.gif'); } );
$('sg6').observe('mouseout',   function() { $('sg6').setAttribute('src', 'images/sg/sg_06.gif'); } );