Say I've built some clipart for my Silverlight application in XAML, or downloaded it from <http://www.xamalot.com>, what is the best way to use it in my app?

Is it best to create a user-control for each piece of art? Or is there a better way that I can reference it from a resource dictionary?

**Update:**

The answers provided are pretty detailed, and seem to be hinting at using this for a much larger purpose than I imagined. I really was just wanting to know the best way of consuming XAML clipart for use as (say) a button on a toolbar.