var url = "http://www.marialouisadolls.com/blog/wp-content/themes/maria/images/";

function button_on_top ( img )
{
  var str = url+img.id+'_purple.jpg';
  //alert(str);
  img.src = str;
}

function button_off_top ( img)
{
  img.src = url+img.id+'.jpg';
}



function button_on_bot ( img )
{
   var str = img.id;
   var limit = str.length-3;
   str = str.substr(3, limit);
   str = url+str+'_purple.jpg';
   //alert(str);
   img.src = str; 
}

function button_off_bot (img)
{
   var str = img.id;
   var limit = str.length-3;
   str = str.substr(3, limit);
   str= url+str+'.jpg';
   //alert(str);
   img.src = str; 
}