- On your syncing computer go to iTunes>Preferences>Devices and see if you do have a backup, if so restore from that backup. When you sync to iTunes the first step is making a backup
- If you use PhotoStream you may be able to get them fromn yuor steam. See that topic of:
Note that the backup and PhotoStream only included photos in your iPod's Camera Roll (or Saved Photos) album. Photos synced to the iPod are not included.