Remove obsolete method

This code isn't used since commit eef8ad1b.

app/helpers/images_helper.rb

@@ -9,11 +9,6 @@ module ImagesHelper
     end
   end
 
-  def image_first_recommendation(image)
-    t "images.#{image.imageable.class.name.parameterize.underscore}.recommendation_one_html",
-      title: image.imageable.title
-  end
-
   def image_attachment_file_name(image)
     image.attachment_file_name
   end