We’re making it easier for your employees to work on the go—and without Internet access—in Google Sheets on the web. With this launch, people can now insert images into Sheets even when they’re not online, provided they’re working in Chrome and have turned on offline access. Those images will be synced once the person gets back online. Try it out in Google Sheets today.
Release track:
Scheduled release and Rapid release
More information:
Access your files offline
Access your files offline
Note: all launches are applicable to all Google Apps editions unless otherwise noted
from Google Apps update alerts http://googleappsupdates.blogspot.com/2015/06/insert-images-into-google-sheets-when.html