It's easy to forget that Amazon has cloud storage products on Android now that Google has started pushing the envelope with Drive and Play Music. Amazon does offer its own photo backup app connected to a free 5GB Cloud Drive block. The app wasn't great, but now that's being addressed with a significant update.
Jumping from version 1.9 to 3.0 should give you an idea how big the change is. Here's the changelog to break it all down.
- New, a completely re-designed Cloud Drive Photos experience with features that bring enjoyment back to viewing photos and videos on the go.
- Simple Navigation: Quickly get to your most frequently used features.
- Sorting: View all your videos in one album, and sort photos and albums by date and name.
- Upload Enhancements: See the progress and status of your automatic or manual uploads.
- Crash and bug fixes.
The updated app still has that dark Amazon UI vibe from the Kindle Fire, but it's more native to Android as far as the layout and buttons. You can see a few pics of the old interface below for comparison. It's also supposedly easier to get around in the updated app (there's a proper navigation bar now), and users report that it's overall faster. All good things, and free.