here is the request and response header

User-Agent Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12
Accept image/png,image/*;q=0.8,*/*;q=0.5
Accept-Language en-us,en;q=0.5
Accept-Encoding gzip,deflate
Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive 115
Connection keep-alive
If-Modified-Since Fri, 10 Sep 2010 00:10:07 GMT
Cache-Control max-age=0

Server nginx
Date Tue, 09 Nov 2010 22:26:50 GMT
Content-Type image/gif
Content-Length 5541
Last-Modified Fri, 10 Sep 2010 00:10:07 GMT
Connection keep-alive
Expires Wed, 10 Nov 2010 22:26:50 GMT
Cache-Control max-age=86400
Accept-Ranges bytes