Quick and Dirty Async Image Loading Plugin (jQuery)

(function($) {
  
  $.fn.imageAsync = function(options) {
      var settings = $.extend({}, $.fn.imageAsync.defaults, options);

      return this.each(function() {
        
        if( $(this).attr('src') ) {
          
          var originalImageSrc = $(this).attr('src');
          var imgHeight = $(this + '[height]').attr('height') || settings.h; // bug in firefox: even if img has no height attr, it will come back as 16
          var imgWidth = $(this + '[width]').attr('width') || settings.w;
                  
          var originalImage = $(this)
            .attr('src','')
            .wrap('<span class="' + settings.progressClassName + '"></span>')
            .parent('span')
            .css('display','inline-block')
            .width(imgWidth)
            .height(imgHeight);

          var img = new Image();
          $(img)  
            .load(function() { originalImage.replaceWith(this); })
            .error(function() { })
            .attr('src', originalImageSrc)
            .attr('width', imgWidth)
            .attr('height', imgHeight);            
        
        }

     });

  }

  $.fn.imageAsync.defaults = {
		progressClassName: "progress"
	};

})(jQuery);