Photos are not in iTunes.
Which photos are you referring to?
- Photos Synced from your computer to a device (such as iPhone/iPod): these photos are in the folder that you specified to be used for Syncing with your device. Remove the photo(s) from that folder or change the folder.
- Photos taken on the device (by the device's camera): these photos are in the device's Camera Roll. Delete them on the device. Optionally, import the photos from the device to your computer and then delete them from the device.