Search in the
documentation for set_header and set_footer to find the proper syntax to fill "Value" and "Options".
If you select an image, you don't have to specify any image options (image_left, image_data_left, ...) but you need to add the control character &G in the value.
If you add the three images, the value must contain &L&G &C&G &R&G or &L&[Picture] &C&[Picture] &R&[Picture].