too_cheap_for_instagram.rb

class TooCheapForInstagram
  def process(item)
    return unless item.is_a?(Potion::StaticFile)
    extensions = [".jpg", ".jpeg", ".gif", ".png"]    
    return unless extensions.include?(File.extname(item.output_path).downcase)
    
    image = MiniMagick::Image.read(item.content)
    image.sepia_tone("80%")
    image.vignette("10")
    item.content = image.to_blob
  end
end

Potion::Site.register_extension(TooCheapForInstagram)