ok, una soluzione con questa funziona anche su IE:

codice:
<script type="text/javascript">
		//<![CDATA[
		$(function(){
			$("#supersized").hide();
			if ((screen.width>=1600)) { var fObj = "flash_all_resolution_alta2.swf" }
			else { var fObj = "flash_all_resolution2.swf" }	
			var gallery = $("<object classid=\"clsid:D27CDB6E-AE6D-11cf-96B8-444553540000\" codebase=\"http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0\" width=\"100%\" height=\"100%\" align=\"top\"><param name=\"movie\" value=\"" + fObj + "\"><param name=\"allowFullScreen\" value=\"true\"><param name=\"quality\" value=\"high\"><param name=\"wmode\" value=\"opaque\"><embed src=\"" + fObj + "\" quality=\"high\" wmode=\"transparent\" pluginspage=\"http://www.macromedia.com/go/getflashplayer\" type=\"application/x-shockwave-flash\" width=\"100%\" height=\"100%\" align=\"middle\"></embed></object>");
			gallery.appendTo("#supersized");
			$(window).bind("load", function(){
				$('#loading').hide();
				$('#supersized').fadeIn(2000);
			});
			
			$(".galleries a").click(function(){
				var ngal = $(this).attr("id");
				$('#supersized').fadeOut('slow', function() {
					if (ngal == "one") {
						$('#supersized').empty();
						if ((screen.width>=1600)) { fObj = "flash_all_resolution_alta2.swf" }
						else { fObj = "flash_all_resolution2.swf" }
						var gallery = $("<object classid=\"clsid:D27CDB6E-AE6D-11cf-96B8-444553540000\" codebase=\"http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0\" width=\"100%\" height=\"100%\" align=\"top\"><param name=\"movie\" value=\"" + fObj + "\"><param name=\"allowFullScreen\" value=\"true\"><param name=\"quality\" value=\"high\"><param name=\"wmode\" value=\"opaque\"><embed src=\"" + fObj + "\" quality=\"high\" wmode=\"transparent\" pluginspage=\"http://www.macromedia.com/go/getflashplayer\" type=\"application/x-shockwave-flash\" width=\"100%\" height=\"100%\" align=\"middle\"></embed></object>");
						gallery.appendTo("#supersized");
					}
					if (ngal == "two") {
						$('#supersized').empty();
						if ((screen.width>=1600)) { fObj = "flash_all_resolution_alta.swf" }
						else { fObj = "flash_all_resolution.swf" }
						var gallery = $("<object classid=\"clsid:D27CDB6E-AE6D-11cf-96B8-444553540000\" codebase=\"http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0\" width=\"100%\" height=\"100%\" align=\"top\"><param name=\"movie\" value=\"" + fObj + "\"><param name=\"allowFullScreen\" value=\"true\"><param name=\"quality\" value=\"high\"><param name=\"wmode\" value=\"opaque\"><embed src=\"" + fObj + "\" quality=\"high\" wmode=\"transparent\" pluginspage=\"http://www.macromedia.com/go/getflashplayer\" type=\"application/x-shockwave-flash\" width=\"100%\" height=\"100%\" align=\"middle\"></embed></object>");
						gallery.appendTo("#supersized");
					}
					$('#supersized').fadeIn('slow');
				});
				return false;
			});
		});
		//]]>
		</script>
sostanzialmente quando si clicca sul numerino, cancella il contenuto del div #supersized e rimette il codice del flash con il percorso del file associato.

ha grosse implicazioni in termini di caricamento o può andar bene?
(per funzionare funziona, sembra)