If what was suggested above doesn't work, see if you can download and install recuva for Android, recuva is a great windows app, but I don't know how good is on Android.
And once you figure this out, for future reference, just activate Google photo and use High resolution backup, it's free without any limits if you use high resolution, and just remember to use the option to backup via WiFi or cell data (if you have unlimited data, if not just leave it as WiFi).