Revert commit which deleted doc images
It looks like this commit deleted quite a few images: https://gitlab.com/gitlab-org/gitlab-ce/commit/54358d6199ea9262c6da23c990df10abffffe53f
Unfortunately not all of them are orphaned, for example: https://docs.gitlab.com/ee/administration/high_availability/README.html#horizontal
We should revert this commit, I think.