Using post with link_to

I have this route:

avatar_add_from_collection POST   /avatars/:avatar_id/add_from_collection(.:format)            {:action=>"add_from_collection", :controller=>"avatars"}

and I am trying to create a link using link_to that uses post. The reason I need to do that is because (apparently) you can't put an image on a button using button_to.

<%= link_to inline_avatar(avatar.fetch_avatar_image(:thumb)), add_from_collection_avatar_path(avatar),:method=>:post%>

brings up

No route matches "/avatars/3/add_from_collection"

If I change the routes file to make this a GET it works just fine.

The link_to looks like

link_to inline_avatar(avatar.fetch_avatar_image(:thumb)), avatar_add_from_collection_path(avatar),:method=>:post

EDIT:

Jade::Application.routes.draw do

  resources :avatar_categories do
    delete :remove_item
  end

  resources :avatars do
    member do
     post 'add_from_collection', :on=>:member
    end
  end

  resources :categories,:addresses,:calendars,:topics,:profile,:news,:account_setting
  resources :boards do
    member do
      get :move
      post :move_category
    end
  end

  post 'avatars/display_collection'
  get "user/index"
  get 'login/index'
  get 'login/new'
  post 'login/create'
  post 'login/authenticate'
  get 'login/forgot_password'
  put 'login/reset_password'
  get 'login/logout' #post?
  get 'admin/index'
  get 'admin/app_settings'
  get 'admin/user_settings'
  get 'admin/avatars'
  post 'admin/avatar_upload'
  post 'admin/update_app_settings'
  get 'news_configurations/index'
  put 'news_configurations/update'
  get 'message_board_configurations/index'
  put 'message_board_configurations/update'
  get 'profile_settings/edit'
开发者_StackOverflow中文版  post 'profile_settings/update'

  resources :posts do
    get :new,:edit
    post :create,:update,:destroy
  end

  match '/login' => 'login#index', :as => 'login'
  match '/admin' => 'admin#index', :as => 'admin'

  resources :login do
    get :index
    post :authenticate,:logout
  end
root :to => "news#index"

end

resources :avatars do 
  member do
    post 'add_from_collection'
  end
end

or

resources :avatars do 
  post 'add_from_collection', :on => :member
end

EDIT

This is wrong

resources :avatars do
  member do
   post 'add_from_collection', :on=>:member
  end
end

use this

resources :avatars do
  post :add_from_collection, :on=>:member
end

But looks like this won't help