Just from our own experience it only updates when it updates/indexes the homepage again. If it's hitting other pages or images it won't reflect the change in the tools section. What is pretty confusing is there is no regular pattern, sometimes it's two days, other times three weeks. What we're still trying to figure out is why it hits some pages and doesn't index them - we never see an error yet they never appear. Both the MSN bot and live bot have hit the page and image files for this insulated tote page and won't index it. It would be nice if in the future the tools section told us why like Google does.