> Oh there's a download all button too, but it does NOT return the original files.
It does return the original files.
Here are two files, one that got backed up off my phone by google photos, which I then downloaded from google drive, and one that I copied directly off my phone via USB:
$ md5sum IMG_20160504_160057648_HDR*
4bcb38a2e3869b4c769301c1664f5846 IMG_20160504_160057648_HDR (1).jpg
4bcb38a2e3869b4c769301c1664f5846 IMG_20160504_160057648_HDR.jpg
The files are identical.