Are you using relative or absolute URLs to point to the image? It's possible that in one instance the base URL for the request is in a different subfolder or nesting level, so that relative URLs to the image will actually hit the wrong place. What I recommend is generating URLs dynamically based on the content root. For example:
<img src="${pageContext.request.contextPath}/images/cdf_hd.gif" border="0" alt="<bean:message key='product-name.cdf.label' />" title="<bean:message key='product-name.cdf.label' />">
You can cut out the alt and title attributes if you'd prefer.
Jon Emerson
http://www.jonemerson.net/