Note that it could take a while - like several minutes - for the Original download to happen over cellular to your mobile device. I just tested this with Amazon Drive (not Google) but it should work similarly:
- turned off WiFi on my iPhone (cellular only)
- force-closed Mylio on my Windows computers (to ensure that Amazon is my only “online” instance of a Mylio device that is reachable by my phone)
- selected a photo on my iPhone that is stored as a Thumbnail, but the Original is synced to Amazon.
- chose “Download Originals”
It took about 3-4 minutes, but eventually the Original appeared in Mylio on my iPhone at full resolution. Choosing “Info” panel confirms this is now an Original: Raw being displayed in Mylio, even though this photo’s Sync Policy is still set to (T)humbnail.
Now if I want to Export this Original image from my iPhone, I can choose the Share icon. HOWEVER note that on iOS and Android, Mylio is limited by the operating system - and may only be able to export a JPEG, not RAW file (should still be full-resolution, though).