Hope you like Google Photos. Starting May 1, Google is going to start phasing out Picasa from its product lineup entirely. Fortunately, you still have some time. If you have any photos stored in Picasa Web Albums, you can access most of them via Google Photos already right now. If you want to continue adding to and editing those albums, you'll have to use Google Photos to do it in the future.
If you don't like Google Photos, Google is going to release a tool that will allow you to view your Picasa Web Albums data. This won't allow you to make any changes or add new albums, but all the data will be available for viewing or export.
The desktop Picasa application will no longer be supported, nor available for download (at least from Google) after March 15. If you already have it on your computer, it will still work like normal, but it won't receive any more updates. Google suggests using the Google Photos desktop uploader instead, and managing photos from the web.
This is a bummer for any die hard Picasa fans left, and Google Photos probably isn't a perfect replacement. Fortunately, it is pretty damn good. Google has been steadily improving the service from its already impressive beginnings back in 2014. Picasa had a good run, but it's a good time to move on.
Moving on from Picasa [Google Picasa Blog]