With Photo Mark-up, you're able to access not only the edited version of an image you've opened with it before, but also the original version of the image before it was edited.
To do this, go to Forms > Saved Forms or Submitted Forms > select the Edit Arrow for the form > select the Mark up button below the edited image. A pop up will appear, which will ask if you would like to view the original image or the edited version.
Select Continue to open the edited image so that you can add to it, or select Original to open the unedited image so that you can make a different edit instead.
