Welcome to the Apple Discussions.
When I export photo images from iPhoto 6 to a Kingston 2GB Data Traveler USB 2.0 flash drive it only shows the files that were exported to the USB drive when I open the USB drive
I’m not sure when else you would expect to see the files.
As to your other problem: My guess is that the file structure of the Mac files is causing the problem for the DVR. Although deprecated now, older files on the Macs had a Data and a Resource fork. It’s this second fork that turns up as a “mystery duplicate” on filesystems that don’t understand them.
Try Export the pics from iPhoto to a Folder on the Desktop. Then use one of
these to strip the Resource forks from the files in that Folder. Then move them across to the DVR. See if that helps.
Regards
TD