Then there are several apps and programs out there that could possibly help you recover the photos. You can try DiskDigger, MobiSaver, Android-Recovery and Tenorshare that can help you recover the deleted photos from your phone.
Please remember though that most of these programs are not actually free. Many will allow for free installation or trials, but to actually recover your data, and get your photos back, you may be required to purchase the program/app.
In the future I would really suggest backing up your phtos to a computer or cloud regularly.