Hi Nikonian, thanks for replying,
I didn't edit them at all.
I did need to download them onto 2 separate DVD's so had to make 2 folders which I named after my friend.
At first I tried to put them back in these folders - no good
Then I put them in DCIM - no good
Then I took a pic and looked where the camera stored it. This was in a folder called 100D7000, so I added them to there - no good.
I noticed that all the files that the computer made were named (something like) DCIM_001, DCIM_002 etc, whereas all the files I had were named just 001, 002 etc. So I tried renaming one of the files to the DCIM style name - no good.
That's all I have tried.
As for why, thats a tough question. I copied the files onto DVD's and a USB memorystick as a double backup, and I didn't expect to put them back, partricularly as she had used up 7GB of the 8GB SD card in the camera.
However, I said that it would be easy to put them back if she wanted, and she said that she did.
Since then, I have told her that putting them back was not as easy as I thought, and that although there are millions of videos and explanations of how to remove them from the camera, there aren't any that show you how to put them back.
I explained that most people want to free up the space on the camera, and be able to view them easily on the TV or PC in a slideshow.
To be fair she seems quite happy to have the photos on backup storage and have the diskspace free on the camea, so it's not really an urgent problem. Really we have got to the stage where I want to understand where I am going wrong, or where I went wrong when I moved them off the camera.
Thanks again