Okay, well I've uploaded 5 gigs of images to Dropbox, and those are directly off the camera.
In another country, my friend with rubbish internet (whom retrieved a CD containing the images) copied the images to a folder on his desktop and began sorting out the images; that is- deleting bad/unneeded images. I can't ask him to upload 5gigs to MY personal dropbox account, when it took me a week to upload with my faster internet.
Is there a piece of software that I can run on his Windows 8 PC to take a list of filenames (directory recursive, since I gave it to him sorted in individual folders for each event); which when then run again on my Snow Leopard MacBook would be able to see which images were deleted on my friend's computer; and then delete them on my side.
If such a program doesn't exist, what framework can I use to programme this (I'm developing on a Mac)? And what tips would you give me?