Chronicle of an announced closure. When Google Photos started doing its thing last May, we all knew automatically that the days of Picasa were numbered. Finally, the company announced the retirement of both Picasa Web Albums and its offline application, but there is a detail: The retirement of Picasa on the desktop is only the cessation of its development; therefore, those who already have it installed, or download it before the deadline, will be able to keep using it.
Picasa has been with us for fourteen years. Due to the way Google accounts work, and the company's own radio silence, it's hard to know exactly how many users it currently has; however, we are sure that some predate the original acquisition of Picasa by Mountain View in 2004. Picasa's features were partially absorbed by Google Plus, but even with the announcement of Google Photos, it managed to retain its position... until now. Last week, the head of Google Photos, Anil Sabharwal, confirmed through the official Picasa blog that the service will be retired effectively on the first day of May. In the case of the desktop application, the closing date is even closer: March 15.
Users who wish to transfer their content from Picasa to Google Photos only need to enter the new service (after all, both share the same database). As an alternative, Google confirmed that there will be a special "read-only" mode for Picasa Web Albums, in which it will be possible to view, download, and delete photos. The other point focuses on desktop software. As of March 15, the Picasa application cannot be downloaded nor will it receive further updates, but those who wish to run it locally have the possibility to continue. It is almost certain that some of its functions, especially those dependent on Picasa Web Albums, will stop working correctly.
In short, users have three options: move their albums to Photos, download them to upload to another similar service, or continue on the offline route managing photos locally, though without official support.