In your JS you have twice the call to $('#dd_image')and in your HTML you have no input named dd_image, but dd_image_one and dd_image_two…
And also in your HTML you have twice id="upload_image_button"and it’s bad :-). This way when you click on the first or the second button you do the same exact call and modify only one non-existent input (#dd_image)
Your button must have two different ids.
Once you’ve changed the ids, the simplest way to make both button work is to duplicate your JS call and change the ids where it should (button and image input)
Hope it’ll work for you.