I was trying to insert a link to an image in my question, but it says
Links cannot contain <IP address> (try a nonnumeric domain or wrap it in a code block)
Because it should show up as an image, I don't want it to be a code block. It should help people understand my question, not make it harder.
I also don't want to misuse one of my domain names just for SuperUser, because it simply doesn't belong to one of the domains. Yes, I know, I could simply register on one of the thousands of image hosters, but why should I do that if I have my own server?
What's wrong in linking an IP address? Actually I think it worked before, because I see that I have uploaded other pictures there already (but maybe it was for StackOverflow).