Picasa is a software application for organizing and editing digital photos, originally created by Idealab and owned by Google since 2004. "Picasa" is a blend of the name of Spanish painter Pablo Picasso, the phrase mi casa for "my house" and "pic" for pictures (personalized art). On 5 January 2009 Google released a beta version of Picasa for Mac (Intel-based Macs only). Also, a plugin is available for iPhoto to upload to the Picasa Web Albums hosting service. There is also a standalone Picasa Web Albums uploading tools for OS X 10.4 or later.

• Add name tags -- Picasa scans all the photos in your collection, identifies the ones with faces, and groups photos with similar faces together.
•  Now you can upload to a friend's album directly from the Picasa software.
• Quickly add geotags using the newly integrated Google Maps.
• Import, upload, and share, all at once -- We've improved the import process so that you can star your favorites, upload to Picasa Web Albums, and share with Google contact groups at the same time.
• Tags -- Better bulk tagging, quick tags & tag counts -- We've improved the tagging experience. Just click the new Tags button on the right side of the Photo tray to add Quick tags, see tag counts for groups of images, and manage tags more easily.

Updates : Picasa for Mac Updates