8. A non-transitory recording medium recording a control program for controlling an operation of an image processing apparatus, said control program causing said image processing apparatus to: generate a first additional image based on an image in a designated region of a first document, generate a second additional image showing a difference between said first document and a second document; said second document being a revision of said first document; and register said first additional image and said second additional image on another device in association with a marker image indicating a revision stage of said first document.
11. The non-transitory recording medium according to claim 8 , wherein said control program further causes said image processing apparatus to print said marker image to replace said image in said designated region of said first document with the printed marker image.