RSS icon not found

I'm using Drupal 4.5.0 with Syndication (2004/10/21).

The image for RSS icon to be displayed on the syndicate block cannot be found.

In syndicate source code:
theme("image", "xml.gif")

And compare it with node.module code:
theme('xml_icon', url('node/feed'))

It seems that the Syndication block links to a custom xml.gif file, instead of using the default misc/xml.png included with Drupal.