Secure Images

Go to Storefront -> My Themes -> Customize. (If your store is a new store, you may need to go to Channel Manager -> Themes -> Edit Theme)

In the Theme Editor -> go to Other Settings / Security Image

Input in Theme Editor limit 64 characters.

Images must be successfully upload to the Image Manager.

When you are happy with your changes, don't forget click Save and Publish to repackage the edited theme.