Mac creates extra folders when transferring from a hard drive

My wife is moving (upgrading!) from a windows laptop to MacBook Pro. I put all of her files onto my hard drive, then plugged it into her new MacBook Pro. When I copied the files across, extra folders had been created out of nowhere. For every individual file, a folder has been created in which contains two versions of the file.

For example the picture 'SDC11919' is there, plus a folder 'SDC11919.JPG.files' and in that folder is 'vcm_s_kf_representative_640x480.jpg' and 'vcm_s_kf_max160_160x120.jpg'

So that's 1 file (which I want) plus a folder and 2 files in that folder (none of which I want) for every single picture we copied over!!

Nightmare!