Trouble with photos taking up double space on iPhone

Had to reinstall Windows 7 today. I have iTunes on one drive and all my media on another. Done this a few times and always just synced moved the folders about & synced with no trouble. Today has been a nightmare and what took 30 mins to sync photos to my iPhone 6 on Friday, has so far taken at least 3 hours and double the space has been taken up.

I can't see any duplicates on my pc or phone. On iTunes it was showing 25gb for 'other' which is the same size as my photos. Not sure what it reads now as I can't click anything until it finishes. But my iPhone is showing way too much on the photos section. Can anyone help please?!