Google have quietly announced an update to Google Photos (v1.18 for those who are interested) that brings with it a manual backup option. So what is it? If you’ve not turned on automatic updates, or we assume if you’re off WiFi and want to quickly upload some images, you simply select the images you want to backup to your account, click the overflow menu (3 dots) and tap “Backup now”. That’s it, those images will be saved to your Google Photos account and you’re done.
I can see this feature being beneficial to those who may not have access to great data allowances but still want to save their more special images. The new version and feature are rolling out today, and if it’s like a typical Google update you may have a few days to wait.
Source: Google+.