Then something is wrong with your api, since it should be working. I expect a lot of these problems are due to your upgrade issues from your other topic: E: Version for 'gitlab-ce' was not found - #5 by saga440
so not sure how you reverted your server, if you restored it from a Debian 8 backup as mentioned, or whether you tried repairing the existing installation without going back to a clean restore before the failed upgrade was attempted.
So obviously if the API didn’t run, then the value hasn’t changed and the problem with the images could still be because of this. Or the API updated the value, but didn’t help. In that case I’m not sure why, maybe someone else will help and add their thoughts to this topic, as I don’t know why it’s not working.