dropboxphoto-sharing
As stated in Dropbox FAQ:
Camera Upload tries to be smart about not uploading the same photos
and videos more than once. It will not re-upload these files even if
you move, rename, or delete them from the Camera Uploads folder.
So, how can I clear this "cache" and reupload all photos again after deletion?
To move between Dropbox Folders on Android:
You should see the file there.
Sign in to Dropbox. From the Dropbox webpage: go to the "Camera Uploads" folder and click on the ones you want deleted. (You can use Ctrl+A to highlight all on that page.)
Then click on "delete" in the top menu.
Best Answer
I'm using the android app and I just go to the "Camera Uploads" folder and select "Upload here" from the menu.
You then get asked to select "Photos and videos" or "Other files". Select "Photos and videos".
Choose the photo you want to upload and select Upload.
If the file exists, it will ask if you want to replace the file.