Well, there is no guaranty of getting them back. Once deleted they are meant to be gone. That said, you 'may' be able to retrieve them through the following.
NOTE: If you had the phone synced to a google account, and updated it regularly, the images may be there.
There are a few apps/programs out there that 'may' be able to help you recover the data.
A few of the programs you could try would be... DiskDigger, MobiSaver, Android-Recovery and Tenorshare. They are all data recovery apps/programs. There are many others out there, so check around and see which you would rather try. There is also one called RECUVA, that I have heard is free, which you could try.
One important note though, most of these programs are not free. They may say...