If you have pictures on the Camera Roll, that will cause the ipod to show up as a drive.
The Camera Roll contains pictures saved from Safari and any screenshots you have taken on your iPod.
Look into the folders (DCIM I think) on the drive and remove any pictures you find in there. If you wish to save them, do so into a folder on your computer. If you want them on your iPod, save them into a folder that is Synced with your iPod.