This is totally one way upload feature. I will not delete any files in the device or in dropbox.If you delete media from device: it is just not synced next time as its not there. The file will remain in dropbox if you dont go yourself to delete it. If you delete media from dropbox: next time you sync it sees that this file is missing (assuming its still in the device) and it will upload it again. I am not planning to make this any smarter. This is a simple publish thing that will keep all your media in dropbox. Youll have to manually remove pictures from the phone if you remove them from dropbox AND want it not to push them again.