How can I prevent a shared folder conflict from happening again?
To prevent a shared folder conflict from happening again, make sure that only one person at a time edits confidential folders and files.
The easiest way to do this is to move your file out of its Dropbox folder while you’re working so that nobody else can access it. Once you're done editing, you can move the file back into its original location.
If you have Google Plus installed on your Android phone with Auto Backup enabled, any new pictures in your camera roll will upload to Google Plus automatically. This includes any pictures downloaded from Dropbox.
To prevent the pictures in your camera roll from automatically uploading to Google Plus, you'll have to disable Auto Backup from Google Plus' mobile app settings. To change your settings, follow the instructions in Google's Mobile Help Center.