iPhone photo upload problem?

So before IOS5, whenever i wanted a photo from my computer, PC or Macbook, i would just copy and paste the photo from the folder on the computer to the iphone folder. Now with the new update, i need to sync the photos using iTunes. I had no problem with this. I put all the photos i wanted into one folder and then did the sync photos with that folder. I however did a mistake before and accidently uploaded some photos i didnt want and now they are on my phone in the new folders created. However, i cant delete those photos unless they part of the camera roll. How do i delete the photos i dont want that are now in the new folders created? Also is there an easier to take photos from the computer and put them on the iPhone? This new update is really making me want to switch to Android. Its a shame i have 6 months left on my contract.