There is something quite odd going on there. Your thumbs don't appear in IE, but the site looks fine in Firefox. That's a new one to me. Probably some type of .htaccess referrer issue.
Outside the images being out of order, (and missing in IE) it's fine by my every-changing standards.
BTW, my stats tell me that Firefox demands less than one quarter of the market - and my stats are the only ones that matter.
IE is 65%+. Safari is around 4-5% and probably growing as more and more users switch to fruit.