background image not display on convert html to image by IMGKit in rails
html_file = render_to_string(:action => "generate_image", :layout => false)
kit = IMGKit.new(html_file, :quality => 50)
kit.stylesheets << "#{Rails.root}/app/assets/stylesheets/template_preview.css"
send_data kit.to_png, type: "image/png", disposition: "inline"
