Which photos get automatically backed up to G+ When using the G+ Auto Backup feature, do only my camera photos get backed up? What about downloaded photos, those that I create, or the ones that I transfer from PC to my phone via USB?

The support page and the Photos app seem to be unclear about this.
From what I have read, the only photos that are backed up are those in the folder named "DCIM/Camera", which should include photos from your camera. If you move other photos there (e.g. downloaded, etc.), they should be backed up.