iPhone sync issue with photos when using iTunes

I sync my iPhone to my iMac every night and as part of this it syncs my photos from my iMac.

However, here is the weird thing: It take many of the photos on my Mac and then often duplicates those photos onto my phone, not a straight duplicate but it seems to split one picture into two as follows:

1. Sometimes one of the duplicated photos is literally blank, with no image, but the location and time/date stamp at the top, and the other is the image with the time/date stamp but no location.

2. Sometimes it's the same as above, but the image may be duplicated on both. 

To clarify, if the original photo was taken on my iphone and then imported into Photos, I will have deleted the original, so I know I'm not looking at a normal duplicate. It's really weird how it seems to split the info into two separate pictures.

If I look at the Photos app on my iMac, there is only one original picture there so it's a corruption problem on my phone that is happening during the syncing process.

When trying to share the photos from my phone for the purpose of this post, it won't let me share the corrupt version ( in option one above, where it is blank) and gives me the error message:

Unable to Share. There was an error while preparing to share. Please try again later.

Instead, I had to take a screen shot and share that instead and I'm now attaching.

Strangely, in option 2 where the image itself is also duplicated, it does let me share that.

Anyone have any ideas?