This is a DayDream (Screen Saver) widget which shows your Instragram's pictures.
This App works from Android 4.2+
To enable go to Setings->Display->DayDream and select Instadream DayDream. If you have it set in "when to daydream" menu and have your phone in the charger/dock it will not turn off its screen but displays this screensaver instead.
Don't hesitate to email us your feedback to android@devsar.com we reply promply.