The Google Photos app was announced at the Google I/O keynote on the 28th May 2015.
Things have changed quite a lot, especially the editing (create Stories from scratch) and sharing. You can share directly to a social network, or choose Get shareable link to send someone a link.
The desktop functions very much like the mobile app.
Now it is very important for you NOT to delete any photos unless you are very sure of what you're doing and where you are deleting them from.
Remember: All your Auto Backup photos and creations are private and visible only to you until you decide to share them!
Goodbye Google+ Photos
Chromebooks will lose the Google+ photos app on the 21st July 2015.
Google will retire Google+ Photos starting 1st AUG: First Android and then Web and iOS version.
+Anil Sabharwal who leads Google Photos wrote a "clarification". The comments on the post show the feelings of Google+ users. +Trey Ratcliff posted a video where he shows how things can be done on Google Photos, but did professional photographers use Google+ photo editor or will they use Google Photos editor? Hey +Adobe Photoshop you have a competitor...
Find your Photos from posts album in Picasaweb, it doesn't exist on Google Photos.
I'm sure there will be more development to Google Photos but at what point? A year from now?
Make sure to send Feedback to Google with your wishes and concerns.