Try this from Google Play
https://play.google.com/store/apps/details?id=com.defianttech.diskdigger
If that doesn't work try searching for UNDELETE on Google Play. Or come up with your own creative search keywords. You'll see a whole heap of recovery apps like thsi. These have varying effectiveness. 5 might not work, but the 6th one might work like a charm.
I've used apps like this before and they worked like 90% of the time for me. Meaning like 9 out of 10 photos would be found and be recoverable, but the 10th one had already been overwritten by other data. Nothing you can do about that situation.
In the mean time, don't take anymore pictures or download big files. Those could overwrite the spot on the sd card where the photos are located.
Im assuming these are photos of a beuatiful woman....so you can thank me if this works by sending me the photos. :laugh: