wrong path for throbber.gif

The path to throbber.gif is wrong -> leads to many page not found entries (and of course throbber.gif ist not displayed)

  $('#edit-picture-upload').change(ajaxFileUpload).after('<span id="loading" style="display:none"><img src="drupalhead/misc/throbber.gif" /></span>');

The path should not start with drupalhead/ (in my case /misc/throbber.gif) works but I think it should be (not tried out)

  $('#edit-picture-upload').change(ajaxFileUpload).after('<span id="loading" style="display:none"><img src="{$base_path}misc/throbber.gif" /></span>');