[Plugin: KNR Author List Widget] Adding Gravatars to Author List?

First of all, if you need an authors list widget that allows you more flexibility, including the ability to limit the number of authors and sort your author list, this is a fantastic plugin.

So far it works exactly as advertised.

I would like to add gravatars next to the author’s name. Anybody have any advice on how to do that? It’s a simple plugin of just one php file, if anybody’s got the time to take a look and tell me where I could add some code for a Gravatar I’d be extremely grateful, and I think it would really improve the plugin. I’m trying to use this as part of some membership directory functionality I’m adding to my site, and I imagine others would find it quite useful.

Here’s a link to my site, you can see the last 10 members (authors) listed in the sidebar: http://www.tacomamama.com/

and here’s a link to the plugin page: http://wordpress.org/extend/plugins/knr-author-list-widget/

and the gravatar section of the codex:
http://codex.wordpress.org/Using_Gravatars