In the Web Portal, you can create a new Form by going to Forms > Start New Form;
Or open an already created Form by going to Forms > Saved Forms or Submitted Forms > select the Edit Arrow for the form.
In the form, add a photo to the photo field in a form, or scroll to where there are added images to the photo field already. Under each image, after they have been added, you will find a button below each image labeled Mark up.
Selecting Mark up will take you to the editing tool, where you can add edits to the image. Once you've made the changes, you can Save the edited image, and then to return to the form, select Exit.