Picasa is a software developed by Google, Inc. whose function is to allow the user view and organize the pictures in his/her PC.
Every time you open Picasa, it automatically locates all your pictures and sorts them into visual albums organized by date with folder names you will recognize.
Through this app, you can automatically back up all of your photos to Google+. All you have to do is log in with your Google account, and the backup will run in the background.
Apart from being a photo manager, this software has useful editing functions so that you can resize, crop images and add several effects to enhance your image quality.
The latest version includes Web Albums, but requires that you request an account from Google.