Yes, you are able to choose whether to view an edited version of an image, as well as the original, via the App. This is only able to be done if you have edited the photo in the App. If it has been changed and the form saved in the Web Portal, then you will only be able to view the edited image.
To be able to view the image, find the Form that you've added the images to via the App. You can select the image and then select the Mark up option. A pop up will appear asking if you would like to view the Annotated version of the image, or the Original.
Select Annotated if if you want to view the edited image, and Original to view the unedited.