Since the watermark can be deleted even if flattened, I am converting the watermarked PDF to an image and then back to PDF. The problem is that I cannot control the page size. The source document is 8.5x11 (Letter).

Fill Page stretches the source document into A4.
Maintain Aspect Ratios crops part of the page and adds white bars at the top in order to fit the source document into A4.
Fit Page to Image maintains the aspect ratio of a letter page however the output is 35.42 inches by 45.82 inches. I receive the same result if I drag the PNG files into Foxit. The PNG files were created using StirlingPDF to Image using the default of 300 dpi.

For all three options, it would be ideal to be able to specify the dimensions of the PDF output. The usual choices will be either Letter or A4 however other sizes, and even custom sizes, might be desirable for some use cases.

As a further feature request, it would be nice to specify global defaults since, in North America, metric paper sizes, although much better, are very hard to find and are very rarely used.

I am running the alpha Docker container with the following digest: sha256:5327c72ff21727812e3841ab3592fc999022d7c2307b00be4dc767234bed55b0