$(document).ready(function(){
  $("#a_fixed_block").click(function(){
  if(!$("#block_fixed_block").length)
    {
      $("body").append('<div id="block_fixed_block" style="display: none;"><img src="'+$(this).find("img").attr("src")+'" /></div>');
      $("#block_fixed_block").fadeIn();
      $("#block_fixed_block").click(function(){
        $(this).fadeOut("fast", function(){$(this).remove();});
      });
    }
  else
    {
      $("#block_fixed_block").fadeOut("fast", function(){$("#block_fixed_block").remove();});
    }

  });
});