Display an icon for a 3rd party plugin in the Welcome Screen Follow

I'd like to display on the Irida Welcome screen the icon of a couple of the plugins I maintain. I've added a logo="" parameter to the vendor tag of the plugin.xml (as in the StarTeam plugin), but the logo isn't appearing on the Welcome page. I suspect that the logo cannot be found by Irida due to a path issue.

How does one get the icon to display?

Thanks.
Eric