Removing Photos from iPhone

Not sure if this is the place for this question. Anyway, friend has an iPhone and a PC Laptop (Win 10). I was trying to remove her pictures from the phone and put them in a folder on her desktop. I was using explorer, opened two windows (one for the iPhone pictures and the other for the destination folder). When I try to cut, paste, the pictures only copied, not "cut". Also when I highlighted all of the pictures to move, only a few would copy at a time. For some reason it would start to copy all of them (over 300 files) and then it would skip a bunch. I would have to go back and do them about 4 at a time. I still have a couple of thousand to go. Can anyone explain what's going on? Thanks
 
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