Yes, you have great possibility to retrieve the pics deleted or formatted from cellphone. Those pics are still in the memory of your phone just not visible, and pics data are waiting to be written over by new data. So from now on don't use your cellphone to take more pics.
Then the best way to retrieve your deleted pics is to use some picture recovery programs. Recommended one is this photo recovery program. Here is the steps you may refer while retrieve your deleted pics from your phone memory.
1. Download and install this photo recovery program
called asoftech photo recovery on your computer. http://www.facebook.com/pages/Asoftech-Photo-Recovery/126127714100611?sk=info
2. With your phone memory inserted, Under "My Computer", note the drive letter assigned to your phone's memory card (usually G: or H:).
3. Start the program and select the drive letter that assigned to the memory, click "Start".
4. Now the scanning process will start automatically to look for the deleted pictures. You will then get a list of all recoverable ones.
5. Select the pictures you want and click "Recover" and you can get back deleted pictures from your phone successfully.