This is a tool which aims to allow designating Picasa's Starred Photos as a John's Background Switcher (JBS) repository. It will have to be ran each time new photos are *starred* to stay current. Eventually, I hope to allow Album support, too.
First, find your Starred Photos list. For me, it was located here: %userprofile%\appdata\local\google\picasa2\db3\starlist.txt
(Copy the above location and click Choose File. Paste in the resulting file locator to select your stared photos.)