Ok, because the moment I saw the picture I accidently reported the wrong report, and instead I gave the warning to the one who posted the picture. But next time I will report it and then I will give the warning. Also, the user that I gave the warning to, its already his second warning or first.
If you do the former, you must inform the staff in the thread that you have done so, which means an smod or admin can close the thread as having been done. For the latter, that's ok as well (more preferred)