Picasa Web Albums Uploader on Mac now allows you to download all photos in your account. To download, sign in your account with Picasa Web Albums Uploader application and select the Existing Album tab. Holding down Mac's Option key will change the title of the Download Album button to Download All. Then one click will bring all of your albums home. Also improved reliability of the uploader's iPhoto export plug-in.

Download: Picasa Web Albums Uploader