Comment outside of controller/Model

[Rubioli]

I have models Album & Picture.

Album model:

class Album < ActiveRecord::Base
  has_many :pictures
  accepts_nested_attributes_for :pictures, reject_if: :all_blank, allow_destroy: true
end

Picture model:

class Picture < ActiveRecord::Base
  acts_as_commentable
  belongs_to :album
end

In my albums#show view, I have all pictures that belongs to the album. I want to add Comments for each picture.

How can I added it? Since now in my controller I do:

#AlbumsController
@picture = Picture.find(params[:id])
@new_comment = Comment.build_from( @picture, current_user, "" )

But this gives me same id for all pictures commentable_id and that id is the album's id.

How can I do this correctly?

Thanks in advanced!