There are various 'undelete' tools you could find by Googling, but I'd hesitate to use them on the internal storage of any phone. If your pictures were stored on the external SD card then it would be safe to use them on that. (personally I would remove the SD card from the phone and plug it in to the computer with one adapter or another, just to keep the phone out of the mix).
I have Dropbox set up on my phone and my PC. Dropbox has an option to automatically upload new camera photos to the dropbox, and from there to the PC. All of this is done without you having to do anything special after you've done the initial setup. This won't help to recover the lost pics, but it should prevent the same thing from happening to any future ones.