Load gif image > execute statement > hide gif

Load gif image > execute statement > hide gif

Is there something wrong with this sequence?
//loading_image is hidden at first
$('#run_only').click(function(e) {
$('#loading_image').show();
//long code processing
$('#loading_image').hide();
});
The gif image is not showing with this code. I tried removing the
$('#loading_image').hide(); and i discover that the loading of image
happens after "long code processing"