new question about deleting photos on iPhone

[jstar222]

I deleted the photos in the Current Roll on the iPhone by syncing with iPhoto. But there are two other folders - Photo Library and Last Roll - whose photos I can't figure out how to delete. I have read dozens of forum posts around the internet and the general solution seems to be, uncheck the relevant folder in the iPhone manager in iTunes and then sync the phone. But I don't have a Photo Library folder to check OR uncheck, and unchecking Last Roll doesn't affect anything. Beyond that I have no idea what to try. Any ideas would be appreciated!