code: func (api UsersAPI) DeleteAvatar(w http.ResponseWriter, r *http.Request) {
  	username := mux.Vars(r)["username"]
  	label := mux.Vars(r)["label"]
  
  	// return a status conflict when trying to delete a protected label
  	if isReservedAvatarLabel(label) {
  		http.Error(w, http.StatusText(http.StatusConflict), http.StatusConflict)
  		return
  	}
  
  	userMgr := user.NewManager(r)
  	u, err := userMgr.GetByName(username)
  	avatar, err := u.GetAvatarByLabel(label)
  	if err != nil {
  		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
  		return
  	}
  
  	// If the link points to itsyou.online, we also need to remove the file stored here.
  	if strings.HasPrefix(strings.TrimPrefix(avatar.Source, "https://"), r.Host) {
  		hash := getAvatarHashFromLink(avatar.Source)
  		err = userMgr.RemoveAvatarFile(hash)
  		if handleServerError(w, "removing avatar file", err) {
  			return
  		}
  	}
  	err = userMgr.RemoveAvatar(username, label)
  	if handleServerError(w, "deleting avatar", err) {
  		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
  		return
  	}
  
  	w.WriteHeader(http.StatusNoContent)
  }
docs: // DeleteAvatar is the handler for DELETE /users/{username}/avatar/{label}
  // Delete the avatar with the specified label