controller.rb

class PhotosController < ApplicationController
  def show
    if params.has_key? :time
      @main_photo = "http://www.google.com/images/srpr/logo11w.png"
    end
  end
end

i18n_helper.rb

module ApplicationHelper
  def i18n_image(path)
    "#{path}.#{I18n.locale}"
  end
end

i18n_image.erb

<h1>Photos#show</h1>
<p>Find me in app/views/photos/show.html.erb</p>

<%= i18n_image "intro"  %>

view.erb

<h1>Photos#show</h1>
<p>Find me in app/views/photos/show.html.erb</p>

 <img src="<%= @main_photo %>" />

<%= link_to photo_path time: "20140820-1800" do %>
- 1 hour
<% end %>