I backed up all my photos to my cloud drive and then found that there's no way to sync photos so they continue to stay updated. (Also read this thread).  I know that you can drag a file into the Amazon Cloud Drive app and when you do, it skips any duplicates. As such, if I want to edit/update any photos (i.e. - in lightroom or photoshop) and then re-backup my photos so that my cloud drive has the most recent version, when I click and drag that file into the app to (re)upload the pictures within, will it replace the edited files with the newest version or just see it as a duplicate and skip it (thereby keeping the old version)? Thanks! 
Amazon Cloud Drive for photo backup - how does it handle edited photos?
photos;backup;synchronization;amazon cloud drive