Uploading Graphics

Can someone please help me with this problem I have.

My site The Blueberry Patch has in the Menu *Tag of the Week* and *Date/Time* sections.

When I upload a new graphic to these areas, they will not show up when I reload the page. It could take up too an hour before the new graphics show up. I have tried clearing the cache, but that doesn’t work. The old graphics are still there.

When I add graphics to posts and pages they come up straight away when reloading the page.

In case you want too take a look the website is http://www.the-blueberry-patch.com.

I would appreciate any help with this

Thank you.
Anita