Google on Friday announced that the Picasa desktop app and its corresponding online photo-sharing service, called Picasa Web Albums, are soon going to be officially dead. This didn't come as a shock: since the launch of Google Photos, Picasa's fate was pretty much sealed.
As of March 15, 2016, Google will no longer be supporting the desktop Picasa application for Mac and Windows. After the cut-off date, existing Picasa installations will still work.
However, Google has said it will cease development of the app so there will be no future updates nor will the Picasa app continue to be available for download after March 15.