Same photos have been imported onto my iMac but have different info in iPhoto

I have photos that I have imported onto my iMac and I am reading from the info panel of each photo in iPhoto. I have the same photo taken at precisely the same moment, but one is just labelled iPad air 2 and the other labelled iPad air 2 then underneath iPad air 2 back camera. Could this have arisen from the fact that I made an album on my iPad from the photo stream or camera roll & it has imported twice ?? Or is this new labelling in iPhoto and perhaps they have been imported into different versions of iPhoto ?? The second photo is smaller i.e. kb rather than mb. I was trying to work out firstly how I had achieved this almost double up and secondly which one to delete. Assume I should delete the smaller version for want of quality. REA