[Zope] image id overlap?

Hi, zopes- I've got a standard_html_header that calls <dtml-var banner>. There is a banner in the root directory. There is a banner in a subdirectory, too. I assume that when index_html is called in the subdirectory, it should show me the different banner. When I switch directories, the image stays the same- but the alt text changes. When i view the image itself, it's what I want, not what gets shown. What gives? -- ~mindlace