You might have noticed a new addition to the application drawer on your Android (provided you have the Google+ app installed) as well as the absence of a long familiar face. You're not seeing things — it's part of the Google+ app update that started rolling out a few days ago.
It seems like most users have the update by now, so they're noticing that the old Google+ Messenger application was removed (the whole service is basically gone, usurped by Hangouts), but it's been replaced by an equally redundant app icon, the G+ Photos app.
We hesitate to call it an app. It's more like a shortcut to the Photos tab inside the Google+ app. There's absolutely nothing wrong with the way the psuedo-gallery-app-thing works or looks, it's just a bit superfluous. It's easy enough to hide with a custom launcher if you just can't deal with it.
Thanks everyone who sent this in!