Stellar Phoenix Android Data Recovery, also shortened to Phoenix Data Recovery, is a free data recovery app that allows the user to reclaim data that was deleted or otherwise lost, on an SD card or a device's in-board memory. It supports photos, documents and other file types for recovery.
The Bumpy Road To Recovery
The app provides enough instructions to understand what you need to do to recover your files, and it lets you specify where the files you want to recover are, and what type you're recovering. It can also attempt to recover large numbers of missing files, in which case you're expected to leave it on overnight. There are two caveats: first, your device must be rooted (granting both yourself and the app full access), and the app simply crashes on some devices.
Worth A Shot
Overall, despite some of the app's flaws, you have nothing to lose from trying Stellar Phoenix Android Data Recovery if your device was already rooted, as some are. On devices where the app runs, it recovers the data you specify and it does it very well. Users who haven't rooted their phone and don't understand the implications should read up on doing so before trying this app.