My iPod has a photo folder from my computer on it, but 'sync photos' is checked off on my iTunes.

When I plug in my iPod Touch 4th gen to my Windows Vista computer, and go to the "photos" tab of my iPod on iTunes, the box that says "Sync Photos From" is unchecked, and all of the boxes in its catagory- all of the photo folders on my computer- are unchecks as well. However, one of those foders in on my iPod. I've tried checking, and then unchecking the folder's box on iTunes, but it does no good. What is happening/how do I take the photos off? They're taking up 2 GB that i'd really like to have back. Thanks!