Hi Lowlihjeng, I use "Android Photo backup" on my Sony tablet s and it works like a dream. It reads my Canon files, converts them to Jpeg (for preview only) and backs up the Raw files on the system memory if required. You can also then send the JPeg preview to other people via Email if you desire. It's available through the google Play store and a free version is offered.
Zuiko 45mm f1.8
Lumix 14mm f2.5