Looking for help with draw.io backgrounds.

I took the approach outlined in this draw.io blog post and it brings the image in to the page though it does not seem possible to control the size of the image. Adjusting the width/height pixel settings is possible but does not change the resultant page. But at least the image is on the page.

My real issue is that when I create the second page and set the first page as the background (as discussed in the blog post), it does not display on the second page.

Controlling the size of the background is one issue but getting the image to display as a background on the second page is critical.

Appreciate any help with this.