http://images inside https://site with proxying in nginx

application_helper.rb

module ApplicationHelper
  def http_url(url)
    return url if Rails.env.development?
    "/http_proxy?url=#{url}"
  end
end

index.slim

# Instead of this
= image_tag 'http://site.com/image.jpg'

# We use this
= image_tag http_url('http://site.com/image.jpg')

nginx.conf

server {
  # Other nginx server params
  
  location /http_proxy {
    proxy_pass $arg_url;
    proxy_set_header host localhost;
  }
}