Kevin Harder created a Graffiti plugin that uses the Slide.Show Silverlight photo gallery control.  This plugin allows you to use Flickr, Picassa, or photo albums stored on your server.

1. Download the plugin, which is located here: http://kevinharder.com/downloads/graffiti/slide-show-plugin/
2. Copy the Copy the Graffiti.Slide.Show.dll file into the /bin folder on your web site. In Graffiti, as an admin, you can do this with Site Options > Utilities > File Browser.  Open the Bin directory and click Add Files.
3. Go to the manage plugins page (Graffiti Admin > Site Options > Plug-Ins)
4. Click the "Enable" link on the plugin you wish to use
5. Click the "Edit" link on the plugin you wish to use to configure it.
6. Enter the name of the post the gallery should be displayed on (i.e. "Photos") and any other options (such as path or username).
7. Click Save button.