= phenomenon =
At the bottom of Mailman's web UI, there is generally three icons at the bottom. An example is http://theoks.net/mailman/listinfo. On the lists.fp.o stuff, these icons are absent

= reason =
The images aren't either in the default location, or a custom location hasn't been specified.

= recommendation =
Reconfigure Mailman to use something like /mailmanicons for the icon root, and create an Alias for that (in Apache) to point to the three icons.