I changed my forum pic but it says success but it is still this.Can we delete our avatar omfg

Check this thread Topic-551538

Your avatar will eventually change. You can ask a sentinel to remove your current avatar by reporting your post and asking for your avatar to be removed through via the report system. However, by asking to remove/delete your avatar, it will not replace it with the new one that is not showing up, it will just leave your account with no avatar at all.
The best thing to do is wait for your new avatar to appear and hopefully this bug will be fixed soon.