RIP: Picasa, Long-Live Google Photos
Google will stop support for its photo service, Picasa, beginning March 15, 2016. This certainly comes with no surprise to anyone as Google Photos continues to be one of the best services out there (for all apps, not just photos).
Picasa was certainly a great product for its time. It was a lightweight desktop application which allowed users to create/edit/organize albums and do simple photo edits (e.g. adding effects) from existing photos on your computer. (Picasa fans will still be able to use the desktop application but there will be no future updates)
Ever since Photos was introduced with Google+, I stopped using Picasa and never looked back.
Google Photos is one of the few apps that I recommend to everyone. The mobile application is the crazy awesome. It has multiple layouts to view your photos (including zooming in and out to show a different of photos at one time), automatic backup to the cloud (including the ability to delete locally stored photos (that have been backed up) if storage is low), ability to edit photos, and the auto-awesome features that include automated creation of GIFs, stories, and videos. The application is a pleasure to use all around and excels at its purpose.
That best feature of Google Photos is the ability to search photos. With Google Image Recognition and using the image's data context, you can search almost anything and it'll come up with photos that relate to it. For example, Tennis:

And you can do a combination of things, people, and places.

While the Google Photos mobile application is best in class, the web application is not as good. You don't get multiple layouts. It's odd that the Google Photos team decided to leave this out of the web app. It's usually that the mobile app is stripped of functionality; in this case, the mobile app has more features.
There is a Google Photos desktop application that uploads photos from your computer automatically to the service.
For most the unlimited high-quality storage is sufficient (particular for phone pictures), but there is an option to store all your photos in full resolution using your Google Drive storage.
I know I write about how great Google Photos is all the time! It's that good!