Squid is missing continously a image

Hello again,

I am experimenting with squid NOVM on a Pentium machine on Linux RedHat
4.2.

I am watching /var/log/access.log and try to load repeatedly different
HTML pages from www.sun.com and I have seen that *every time* , squid
forces the direct loading from sun for an image from the main home page,
with the message TCP_REFRESH_MISS.

TCP_REFRESH_MISS/200 29792 GET http://www.sun.com/971027/11.3.IMAP.GIF -
DIRECT/www.sun.com image/gif

The image is used with a map.

Do you have some idea why this image cannot be cached ?

Please cc me since I'm not (yet) on this mail-list.

Thanks a lot,

-- 
Constantin Teodorescu
FLEX Consulting Braila, ROMANIA