How do I delete pictures of my iPhone which wont delete?
Temporarily enabling icloud photo sync deletes all the itunes-sync'd photos.

Tried all these solutions, nothing worked. However, toggling icloud photo sync worked for me, because iOS won't let you sync both ways (itunes and icloud).


If you don't want your camera roll going to icloud, import all of your photos first with image capture, then delete your camera roll so it doesn't upload anything.
Settings > iCloud > Photos > Enable iCloud Photos
Prompts: "Syncing photos ... is not supported ... Remove Photos and Videos"?
Click ok. Important: I had 20,000+ sync'd photos and I had to re-do this about every 7000 photos or so. 
Go over to your photos app and watch the numbers drop on "selfies", "videos", etc
Turn iCloud photo sync back off Settings > iCloud > Photos > Disable iCloud Photos
The folders will remain (but no pictures in them)
Plug the phone in via usb, launch itunes, sync one small pictures folder. This will remove all the remaining empty folders from the previous sync.