How to edit a photo while still keeping the original?

To retouch a photo, select the patient, then the photo to be retouched.

Using the toolbar located in the viewer, you can retouch the photo by applying various effects.

(Click to enlarge)

(Click to enlarge)

After having saved the modifications of your photo, you can see on the thumbnail of this one, the logo of a floppy disk located on the upper left corner.

This logo tells you that this is not the original image.

To return to the original, select the image in question, then right-click on it. A menu appears. Choose "Picture" then "Back to original".