get base64 string (edit)

<script type="text/javascript">
document.observe("dom:loaded", function() {
  var reloadurl = 'ajaxcontroller/images/load';
  //var images = [];
  $$('.products-grid *').each(function(member) {
    var elDiv = member.firstDescendant();
    var elImageUrl = elDiv.innerHTML;
    if (elImageUrl) {
      member.select('.loadingmask').each(function(element) {
        element.show();
        new Ajax.Request(reloadurl, {
          //method: 'post',
          //contentType: 'text/html',
          parameters: 'imageUrl=' + elImageUrl,
          onComplete: function(response) {
            element.hide();
            alert(response.responseText);
          }
        });
      });
    }
  });
});
</script>