Picasa is a program created by Google to help you manage all the photos you save on your computer. This program not only organizes your photos but also allows you to edit them, add effects and share them with other users over the Internet. Note: The Picasa download is no longer available. The program has been withdrawn from the market to be replaced by the Google Photos service.

What are the key features of Picasa?

Organize: Picasa can scan your entire hard drive or specific directories to find and catalog your photos.
Edit: It includes a handful of basic editing tools: crop, straighten, and adjust color and light, among others.
Share: In addition to the above, the program makes it easy for you to publish or share your pictures, either by email, Blogger, or through Picasa Web Albums, a picture hosting service maintained by Google.
Interface: One of Picasa's biggest advantages is its intuitive interface that makes the program easy to handle for everyone.