[jQuery] Progress image swap

[Trans]

Hi--

I'm pulling my hair out trying to make this work. I want to change an
image to an animated gif to indicate progress while I pull down some
files via synchronous ajax, and then switch the image back to a static
one when finished. Everything I try fails, invariably the animated gif
doesn't become visible until all the ajax loads complete, and then of
course it gone. HEre the basic code I have at them moment:

  $("#meter").attr("src","img/meter_on.gif").show('fast', function() {
    load_stuff_with_ajax();
    $("#meter").attr("src","img/meter_off.gif").show();
  });

Any help will is greatly appreciated. I can;t tell you how sick I am
of reading tutorials saying how easy AJAX is when the simple things
like seem impossible to figure out.

Thanks,
T.