Windows/Mac/Linux (All Systems): One fine day in the future, Google will release a Picasa client for Mac OS X, making it possible for anyone to upload or download a Picasa Web Album from any system. Until then, tools like Bradley Beach's PicasaWebalbumsAssistant will help a great deal. Beach's Java-based tool lets ou grab either public albums by entering a username, or private albums from an emailed invitation link. Better still, it offers thumbnail previews of the album you're about to download, and you can skip shots you don't need. Combined with the previously-posted, OS X-only Picasa Web Albums Uploader and Exporter (original post), Mac users can easily use Picasa's web features without a long series of file choosing and uploads. PicasaWebalbumsAssistant is a free download that works with any system running Java 5.5 or higher.