I don't think we've ever given out a warning for anything image related. There was a POW that we asked the member to change because it was deemed to be slightly inappropriate to be posted on every page of the forum. It wasn't a big deal, no warnings were given and the picture was swapped for another one.
BTW, I personally don't like the term "reprimand". This term usually invokes feelings like: rebuke, reprove, scold & lecture... not very nice.
We're trying to make sure that the terms we use to represent this system are accurate, and we're hoping that everyone will understand the purpose of this system. The definition of a warning in the sense we use it = "cautionary advice"
We want all our members to have a pleasant experience here on the forum. Sometimes we have to give cautionary advice in cases where behavior makes a pleasant experience less likely or impossible.
One other thing this system does is make moderators more accountable for actions because what they do is recorded. So no moderator can take action that can't be reviewed. So the real pressure of the system is put on us now.