Unintended _footer hook generates invalid HTML page

Fron the look of the code I dont think this was intended, but node_image_footer() gets registered as a _footer() hook. This function is seemingly to be used internally to generate the content </body></html> for popup windows. But unfortunately this content is also getting added in every drupal page when theme_closure() is called. Just take a look at the source for http://www.gworks.ca to see the invalid HTML page (with two </body></html> tags) being generated.