How can I stop effect causing page position to jump to container location?

How can I stop effect causing page position to jump to container location?

I have a page with a very basic photo roller across the top followed by a lot of content. I am having a problem where when you scroll down to read the content, the page location jumps back up (scrolls up)  to the roller when the jquery effect executes. Here's the way the roller is written:

A UL contains pictures in LI elements that are all display:none. A timer is set on page load which when it executes moves an index counter to the next value and sets all LI display:none. The index counter is then used to get the nth LI and change its display to list-item via $(item).show('slow').

If I remove the effect of "slow" from showing the item then it doesn't jump, only when there is an effect does it jump.

Any thoughts on this one?

thanks, Jeff.