Carousel is a handy app for both Android and iOS is aimed at those who already use Dropbox to back up their photos and videos. It also has inbuilt messaging for privately sharing media with your friends, which is a bit like what Instagram recently added.
Unlike Instagram, all photos are saved in full resolution. It automatically backs up all photos from your iPhone as you take them and groups them by date and location. A small but useful addition is the ability to hide photos from your collection instead of deleting – and losing – them forever.
https://www.carousel.com/#download