Picasa Webalbums Assistant is a simple Java tool that enables you to download complete photo galleries (or just selected pictures) from Picasa albums without having to install Picasa.

This means that if you're a Mac or Linux user (or a Windows user who don't like Picasa) you can access Picasa web albums just the same. The program downloads public albums by UserID or by copying and pasting an invitation link (for private albums) and also offers thumbnail previews that allow you to download only the photo's you want.