Preamble
From Is there a Raspbian image with OpenCV 3 pre-installed?, these link only answers
To add to @MilanToth’s post, this is a tutorial to expand the partition:http://dracoy.com/2016/06/26/expanding-partition-on-sd-card-for-raspberry-pi-with-noobs-pre-installed/
This, link may be helpfull. The image contains the last raspbian SO (Stretch), Ros and OpenCV
https://medium.com/@rosbots/ready-to-use-image-raspbian-stretch-ros-opencv-324d6f8dcd96