How to delete a photo album on iphone 4 when it won't show up on sync?

I have a photo album on my iphone 4s that I want to get rid of because I don't really have that much room. It's an album on my computer so I can't delete it straight from my iphone, but when I go to the photo sync on itunes the sync photos box isn't checked so there's no way for me to delete it from there. How can i delete the photo album without needing to restore my phone?

Added (1). I understand you have to uncheck what you want removed from your phone but the problem is when I click on the photos tab nothing is checked, therefore there's nothing I can uncheck, but the album is still on my phone.

In order to change what is synced to the phone you have to check the photo sync box in photos.

This will allow you to go in and uncheck the album you want to delete.
Then apply
Then sync.
Same for music, Apps, etc. You have to check "Sync" in order to have access to change the content.