Google has done a good job at adding filters and other tools to enhance your pictures within the Google Photos app. And now they've added a new feature that will keep many people happy. And that is the ability to keep your original photo along with your newly edited ones. So this way if you get a little carried away - we all do it sometimes - in over-filtering photos, or saturating them, etc., you can still have the original available for you to use if you wish to do so. Definitely a good idea, as sometimes we liked the original photo the way it was without any filtering or editing being done.
This part of the update that brings the app to version 1.17. If you are using a version that is lower than 1.17, then you likely do not have the ability to keep the original photo as well. This feature is automatically turned on, and it appears to not be a toggle. So you can't toggle it off, which is likely a good thing. Especially since Google offers up unlimited storage for Photos, there's no harm in keeping the original and then the edited versions, even if it was cropped to much.
Google Photos has done pretty well since being removed from Google+ and being its own service last year. Google Photos can automatically back up all of your photos to your Google account when connected to WiFi (there are also options to only do it when charging, and to allow it to back up over LTE or mobile data). Google can also create collages for you automatically, as well as stylize your photos. There are some pretty sweet filters that Google puts on your photos, that may make you like it better than the original. Google Photos allows you to pick and choose which folders on your device to backup. So you can choose to backup your camera only, or everything else including screenshots, Instagram, Whatsapp and other folders on your smartphone. All of which are available on your other devices as well as the web. Google Photos should be pre-installed on your Android device, but if not you can download it from the Play Store here.