Is it possible to set background image to the slide object itself?

[Peter Wang]

Hi, I am trying to create a pptx file using data from a json file. I am trying to separate data for the slide itself(e.g. background color, width, author, etc) from data for the objects in the slides(e.g. texts, images, shapes, etc) so that I can create reusable template slides. I am having trouble with setting background image to the slide object itself because right now it only has 4 properties(name, back, color, creator) as described in the docs. Is there any way that I can set a background image to the slide object other than adding an image with the size of the slide?

Thanks