= simple_form_for(@images_event) do |f|
  = f.error_notification

  .form-inputs
    - if params[:event]
      - param = params[:event]
    - else
      - param = @images_event.event_id
    = f.input :event_id, as: :hidden, input_html: { value: param }
    = f.input :position, as: :hidden, input_html: { value: @event_position }
    = f.input :image

  .form-actions
    = f.button :submit