I think since the theme can render the upload dialog inoperable, there should always be footer-picasa_album_uploader.php and header-picasa_album_uploader.php files installed. I added:
to picasa-album_uploader.css to get rid of any background defined in the theme and wrapped the div used to display images:
$content .= "<div class='picasa-album-uploader'>\n";
// Start div used to display images
$content .= "<p class='pau_header'>Selected images</p><div class='pau_images'>\n";
} // End Class picasa_album_uploader
I don't know if there is any way to automate installing the files when the plugin is installed - haven't had time to look into that.
I did just run into an issue with installing the Picasa plugin on Win XP. Picasa recognized the plugin file type and started the install, but then never added it to the list of controls (or even displayed the list). So far I've tried three different systems, Win7/64, XP, Vista and it's only failed once. When I can get my hands on the machine that failed I'd like to take a look at why it's failed.
This plugin is great. Last week I put it on a client's machine (client who doesn't even understand file systems and loses their photos on their computer) and she's doing just fine with it.