Hi, we have a top bar on our website that we continually change for special holidays and announcements and such.

Right now we're doing a Christmas theme. When we redesign it and slice it up, we just replace the previous slices with the new images, keeping their names exactly the same, without touching the HTML and CSS.

Problem is our readers sometimes still see the old images, since it was cached on their machines.

What can a person do to ensure they see the new images. If they refresh (CTRL + F5), they'll see the new images, but no-one refreshes websites.