Navigation buttons ghosting on pages

[revlry]

We are having a recurring problem of navigation button images "showing up as enlarged ghost images behind other parts of a web page. When we republish it goes away however it comes back again. An example is on this page: http://unityofdavis.org/sundays_at_ucod.html where you there is an image of the nav button "Unity in the Community" appearing in the middle of the page. We submitted a support ticket and followed their advice to reset Cp password and recreate the nav buttons. But the problem continues

Can you advise a fix for this?
Thanks