function openOverlay(path, alt){
	$('#big_img').attr("src", "images/original/"+path); 
	$('#big_img').attr("alt", alt);
	var img = $('#big_img');
	var pic_real_height;
	$("<img/>") // Make in memory copy of image to avoid css issues
    .attr("src", $(img).attr("src"))
    .load(function() {
        pwidth = this.width + 24;
		$('#overlay_close').width(pwidth);
    });	
	$('#image_overlay_container').show();
	$('#overlay_bg').show();
}
	
function closeOverlay(){
	$('#big_img').attr("src", "images/loading.png"); 
	$('#image_overlay_container').hide();
	$('#overlay_bg').hide();
}