picture.rb

# app/admin/picture.rb

ActiveAdmin.register Picture, namespace: :sales do
  config.filters = false
  config.clear_action_items!
  config.clear_batch_actions!

  actions :index, :show, :edit, :update

  sidebar I18n.t('active_admin.sidebars.search'), only: :index do
    # define sidebar here
  end

  index as: :grid, columns: 4 do |picture|
    # define index here
  end

  show do
    # define show here
  end

  controller do
    def scoped_collection
      collection = end_of_association_chain
      collection = collection.for_projects_containing(params[:s]) unless params[:s].blank?
      collection.recent.ranked # <== apply your sorting here
    end

    def apply_sorting(chain)
      chain # <== return the relation without ActiveAdmin's default sorting
    end
  end

end