create_action_in_controller.rb

  def aviarycreate
    @photo = Photo.new
    @photo.user_id = current_user.id
    @photo.remote_image_url = params[:url]
    @photo.save

    respond_to do |format|
      format.json { render json: @photo }
    end
  end

postImage.js

function postImage(imageID, newURL) {
	        	$.ajax({
	        		type: 'POST',
	        		url: '/aviarycreate',
	        		data: { url : newURL},
	        		headers: {
      					'X-Transaction': 'POST Example',
      					'X-CSRF-Token': $('meta[name="csrf-token"]').attr('content')
    				},
	        		success: function(msg) {
	        			console.log(msg);
	        			
	        			//console.log(msg.image);
	        			//console.log(msg.image.url)
	        		}
	        	});

share_template_i_want_in_new_iframe.html.erb

Hello from /share!

<%= @photo %>