One thing to copy someone's picture.
Now you are whining that someone's copying your picture. But you copied someone else's picture and yet you are whining someone copied your picture.
Wait what the crap?
Indeed, if you had a custom avatar and he stole it he would've been a big idiot.
But you stole a avatar with unknown source and whining about someone else stole "your creation" althrough you stole someone else's.
I'd say not to whine someone stole your avatar unless you made the avatar yourself.