This is an excerpt from our Picasa Beginner’s Guide – see right sidebar for details.
Google+ Auto-Backup: When you installed Picasa you were probably given the option to turn on Google+ Auto-Backup. If you did that then every picture on your computer is being backed up to your Google+ Photos account in a folder called Auto Backup. If you don’t want this, you should uninstall the Google+ Auto Backup program. If you keep it there are settings you must check. When you launch Google+ Auto Backup click the button to Get Started.
To see your backed up photos, go to www.plus.google.com and log in to your account. From the left side dropdown menu under ‘Home’, choose ‘Photos.’ Under the ‘More’ menu option, choose Auto Backup.