Here's a nice overview of resources in avalon. In particular it showed me how to easily display embedded images. There's a follow-up on the pack uris as well.
http://nerddawg.blogspot.com/2005/11/resources-in-windows-presentation.html
http://nerddawg.blogspot.com/2005/12/more-on-resource-loading-in-wpf.html
Meanwhile here's a screenshot of my current Avalon effort, an implementation of the board game Carcassonne. Unfortunately you don't get the pretty fade-in/out in a static screenshot
